+1 on possible permanent disc damage due to incorrect form. Even only lifting ~body-weight it’s easy enough to ruin a lot of future bike rides/walks etc. Herniated disc puts pressure on my left leg sciatic nerve – sore down my hip/leg and bit pins and needles under my foot

I was told a risk factor can be tight hamstrings which are fairly common amongst cyclists

Lift safe everyone!

coupled with barely drinking booze, the teenage would point and laugh at grown-up me not drinking proper tea. In other news, I don’t think I understand denim trousers anymore, but I’m clinging onto hoodies instead of cardigans

Other plant teas that I like: nettle&peppermint, Pukka 3 Tulsi & the Yogi tea one with ginger and hibiscus

Decaf earl grey is alright…Red bush chai is nicer (think made by dragonfly and has spices in)

+1 on caffeine not working for me. I love really decent flat whites – but puts me on edge and I find much stronger urge to drink alcohol in eves, then poor sleep and need coffee in the morning…cycle accelerates away from me

I make exceptions for caffeine if I’m outside for a big day and it’s hosing down, or if I need to drive and I’m tired otherwise I avoid it altogether

If it was really £8.5k, assuming safe product life of 3 years, then that works out at £54 a week, or a couple of ‘nice’ coffees a day. Compared to hobbies like scuba-diving or motor-sports, it’s cheap as chips! I’m guessing the market could stand at least a £20k price tag for a really best-ever mountain bike. It’s possible that days out riding are some of the most enjoyable in a person’s life – so it’s pretty much limitless how much folk will pay – especially as we move to more pay-to-ride, resort based riding.

cheers for warm welcome & great posts all : )

I just re-read thread and made a tally…I make 5 counts of riders with both air & coil experience choosing coil and 2 counts of riders with experience of both picking air rear shocks

I was half sure I’d also read about an Spec.Enduro rider posting about preferring with a Oilins(sp?) coil rear shock but can’t see that post now (deleted?)

Also, it seems like the 2 counts of choosing air over coil were on 160mm travel bikes.

So, on the face of it, it’d be interesting for a magazine (hint!) to run a test, setting up some trail bikes with both types of shocks and seeing how folk get on. I’m not really expecting most mainstream mtb mags to pick up on a topic like this – it’s dawning on me that rather than unbiased reviews they’re mostly just paid advertorials from manufacturers.

“160mm bikes these days are almost as good as 120mm was just a few years back so why would anyone go for less when more is always better?”

Hmm…the chit-chat about the 2015 Banshee Phantom via bikemag.com is worth a listen:
2015 bible of bike tests – banshee phantom[/url]

Thanks for the other tips – but I’m still coming back to the 29er, 105mm travel Phantom (with probably a coil shock) as close to ideal for wild-trail, all-day riding. I’ve read somewhere else about riders having tried 160mm bikes but then coming back down in travel again.

“buy better tyres?”
Well I tried eh – honestly the fattest I could squeeze into the back of that bike was a Maxxis Advantage 2.1″

“a very poorly made bike that was unsuitable for your needs”
No disagreement from me! : )

“coloured by the fact…”
No doubt, but one useful insight from the whole experience was that, the rear shock itself & mounting hardware really let me down and it was totally transformed switching to a coil. So can you imagine if that boost in performance was coupled to a frame that went in a straight line – ideal! – except there’s still not a single rear coil ~110mm bike on the UK market.

“the pro DHers are, and they’re increasingly turning to air.”
It’s quite a (popular) niche style of riding tho – there’s lots of flat-out pedally sprinting at every opportunity in-between trickier sections…do they run them with a switch to flick to gain a few extra seconds?

Are the runs really only1/3 of the duration of an Enduro descent? How come the downhillers don’t ride down the whole hill then?

“Did you buy a Sunn Shamann from CRC?”
y – inappropriate bike selection. Crazy bargain price of £799 & the sense that as a 42yr old timid trail rider after long days out in the hills, a marathon xc style bike would be more than enough for me.

The distinction with motosport and mountain-biking is really significant – on a pushbike the engine pressing down on the pedals is bound to squish the suspension – unless it’s de-activated a bit with a ‘platform’ or lock-out. That sort of thing might be ideal for firetrack climbs or competitive xc with wins happening uphill.

Interesting that the only air rear shocks for motorbikes that FOX lists are for mini-moto bikes. Seems like the coils must perform better for them to justify the extra racing weight. I get that for bicycle racing an extra pound might make a podium difference – but for trail riders, maybe folk would like better performance and durability instead? It all seems a bit topsy-turvy for now, 29ers not generally viewed as burly trail machines – and 160mm enduro rides equipped with cushioning to land doubles rather than deal with natural obstacles – ok so I don’t jump but I’d have thought it’s pretty average what I want a bike to do.

What I’m suggesting is that a ~110mm coil bike left fully open might be perfect for a big slice of trail riders – that way the suspension can really help with traction climbing and out in the hills the ups might be just as rocky as the downs.

“1x transmissions”
Having a narrow/wide at the front with a clutch rear mech is brilliant – fan here for sure and it makes a lot of sense. But I used to run a 22/36 (0.61) gear and that’s welcome late in the day compared to 30/36 (0.83) stock gear on current Oranges – OK possible to select a 30/40 (0.75) on their website but not enough to get rolling on a steep tech climb. If they can’t spec a 28/45 (0/62) at point of sale then it’s just missing the needs of trail riders a bit. Sure – get fitter legs etc! But it’s always ultimately going to be the reason to have to get off for a steep and then tricky to get rolling again. To be honest I’d be happy to run something like 24/45(0.53) thru to 24/10(2.4) on a 1×10 setup – I’ve not found the need much to spin out big ring gears on tech descents.

“Gwin and Remi amongst others choosing air shocks over coil for dh tracks like Lourdes”
A lot of results are to do with the rider – wasn’t Steve Peat winning local early races with 1.5″ tyres on a hardtail? Also, that Lourdes result was enough of a unexpected result that FOX took out full page results in the mags. This is the same FOX that provides a one-off prototype coil shock with a lockout to the reigning male Enduro champ too.

“being in a bike shop and pretty much once a week you were guaranteed to encounter someone with all of the OPs complaints”
So, the obvious conclusion is that we’re all wrong?

My experience might have been really unusual and soz for text walls : ) but I’m on about a nearly £3k new bike from 3yrs ago equipped with rockshox monarch that blew its seal and left me out on the trails with 5hrs ‘riding’ to do as it clunked heavily on fully compressed. Even before that when it was running ‘OK’ hitting rocks would just pinch flat a crazy amount of times with anything less than pinging 45psi – the transformation of ride after swapping to a coil shock was honestly like a brand new bike. I was reading a review of another bike recently & their justified gripe was the rockshox air fork blowing the seal totally off the lower stantion mid-ride. I’m not disputing that sussed out air shocks esp with a negative chamber can perform well – but even if the only rationale for coil was that at ‘failure’ you weren’t faced with a looong walk home then it’d justified to take into the hills – but my feedback of – ok not brand new kit but 3yr old stuff was the step up in performance was incredible!

“Current full suspension bikes are sensational”
No doubt.

“With correct maintenance most will go on for many years.”
Not so convinced about the second bit – for a start it’s pretty likely even basic stuff like size of wheel axles will have ‘evolved’ forcing buying the whole thing over again. But sure, as the sport moves more towards snowboarding with resorts and infrastructure in place then it’s still a much cheaper hobby than some other alternatives – a buddy of mine windsurfs and has all sorts of sails/boards for different weather – most of which he just runs for a couple of seasons and then replaces.

“sektors coil or air?”
solo air. They’re set up for now with one click of compression and five clicks of rebound (I just checked and that’s 1/4 of the way from the hare towards the tortoise sticker). Running with enough air inside to let me have 130 travel on regular rides – with an extra 20mm I guess for clumsy hitting into something. I’ve tried around a few possibilities and seems like that works ok for me – but they’re not very sensitive to small bumps. It’s hard to compare rides – but my call is that the ancient coil Marzochi Z1s, Judys and Fox VanRs (while they worked) did a much job at dealing with vibration and working like suspension rather than just cushioning against bigger bumps.

“Banshee owner”
That’s really good to hear – I only had a scoot on the Phantom but it felt sorted. I’m a fan of them using tubes at the back with an extra reinforcing bit inside to make a sort of boxy sideways 8 cross-section, that’ll do heaps to stop them twisting so much. I was just nervous thinking that the interface with the adjustable part would be a creaky soundtrack all day and wasn’t sure if the soft aluminium would wear a bit there – but no doubt they’re designed for bigger hits than me gently rolling along. Really felt like a fun snappy ride – keen to test again. Sounds ace being able to run a second set of fat wheels for off-groomed trails too : )

“Why would a Canyon Strive not be working in 3 years time? Seriously, explain why please.”
Ah I don’t mean to worry folk – I’m sure it’s reliable enough. It’s just that with rotating load bearing surfaces, not very well sealed against the elements, with a dollop of grit on top are going to wear out fairly soon – but not in a bad way – just in a having to replace a few bits of it – and it’d just show up as a bit of clunk first rather than something to spoil a ride. That office-chair-technology activating bit to change the geometry adds complexity too that might not last for ever – in addition that bit rotates around heaps more than without so it’ll wear faster. Plus any play that develops is sort of amplified on account of it happening in so many places. But none of it’s going to cause any tumbles and I agree regular maintenance is essential – I bet they’re heaps of fun to ride too!

“you just seem grumpy and upset”
I am a bit – nothing major tho. I’d just about settled for a steel hard tail again and was loving just getting out riding heaps – but it’s not agreeing with my back and it’s different looking back at bouncy bikes again – maybe it is possible to keep the same frame running for 10yrs or whatever (especially if it’s part of a £6k push bike) but I’m more thinking it’ll be stuff to break on the trail and spoil a ride (in-between lots of it being genuinely the best performing mountain bike that has ever existed)

“the idea of technology moving on is just wrong”
I’m just a bit unsure all the technology is moving in an appropriate direction for general trail riders. I’m not being a Luddite about it – I’d love to see hi-tech ideas but applied more towards durability and decent product life – instead of a crazy tide of never-ending ‘industry standards’ so that a fork of a few years ago doesn’t fit a frame of today, or last bikes wheels are a different sized hub to the next new frame etc. It just feels a little bit of a sneaky bid for the most cash from bike makers – rather than a fair swap for decent long life kit at a fair investment. Honestly if there was a bike out there that didn’t use polymer bushes, had decent sealed cartridge bearings, a frame that went in a straight line through rock garden bits, came with coil suspension – but designed for trails not gravity runs I’d throw maybe £5k at owning it – everyone else must be looking for a different sort of ride I guess.

Good call on the 5 – and I know it’s shallow of me – but I’m unimpressed at them not speccing a 5/segment with a double up-front – almost like they’re aiming more at trail centre commuters. I didn’t have that Shamann long enough to fuss over the multi-pivot bearings as they were working alright for a couple of years – but ordeal of the bearing cold-welding itself to the earlier sub5 frame doesn’t encourage me about general durability of moving parts

*daydreams ideal bike*
I think possibly 29″…bit sturdy but probably around ~120 travel, wonderful if it had a slightly rearward axle path for hitting bumps coming downhill – so nearly like that Banshee Phantom then – except without the dumb idea of different places for the rear wheel – also lots more tyre clearance or even scope for +tyres sometimes. Coil shocks probably front & rear (I know it’s budget but my 150mm sektor for now is a bit sketch – if it’s soft enough to work as suspension then it does epic dives with braking but set up bit harder and the static friction/stiction means it only really moves with thud on the trail rather than working like suspension to take out vibrations – to be blunt my coil 100mm rockshox Judy of 15yrs ago was a better ride)

ha – I just read in MBR letters about a bike suggestion and their pick was a Canyon Strive – so a multi-pivot bike with an extra adjustable office-chair-technology part, extra bushings and another lever – Good Luck for that working in 3yrs time!

I reckon start at Rhyslyn – then it’s a cruise up a forest road to warm up for 30mins – only slight incline then well signpost to get started with half of the Wall – then traverse and Wrights (with the bike shop/cafe half way round that) then there’s <ahem> a bit of a climb to the windmills – then it’s rocking swoops back to the traverse and sort of 3 slices of more downhill of the second half of the wall (again with a lodge/jump park bit/snacks half way round) – before lovely zig-zags singletrack back to within sight of where you started. Grand day out : )

^what they said.

In fact, it’s just 2 red loops (wall/wrights) joined into a figure of 8 with a short linking traverse of forestry gravel road. There’s only one ‘obstacle’ half-worth dropping a seat for even – a sort of 4 bike length little chute paved with rock slabs – even that’s just roll over. Mostly single-track sections linked with a bit of forest road all the way – surface drains well in all weathers, mostly only planted grapefruit sized stones under tyre at the roughest but fair bit much smoother. Really decent riding tho – one section of small jumpy bits but only low table-tops and a nana line option. 2 snack options & a bike shop nearly en route.

There was a sign flagging there’s a race up at there this coming w/e 15th/16th – disruption on sections for maybe friday too.

It is fairly long tho – maybe 6hrs (ish) / something like 1500m of climbing

“Transition Scout”
looks decent – cheers for tip : )

I didn’t really have a problem with the main pivots on the 4-bar, no grumbles from them even with a couple of years of neglect, it was the shock mount bits that wore out to give a bit of play – I mean it still basically went in a straight line, but it was possible to lift the seat up a tiny bit before the back end would follow if that makes sense and it just seemed a bit naff after less than a week of winter. The mail order co sent me new bushes and we had chats about if there was any other mounting system and confirmed with another shock tuner that it’s just par for the course for now. I had much better life out of the bushes with regular riding – maybe 6 or so changes over a year – but there must be something gnarly about proper grit!

that makes sense about bearings being designed for regular spinning, being a bit uncomfortable with just oscillating a bit instead. In general, I’d bet money too on a lot of the computer analysis mostly modelling the bike in a horizontal orientation with a vertical load – rather than the angle forces hit the rear wheel on a descent – let alone trying to factor in much of a side load from the drive train being unsymmetrical or cornering twisty forces too – the sums just get a bit fiddly – so much of it is prototyping and re-design (hopefully!)

“as a crack-stopper”
this might be in the context of an extra hole at the bottom of a slotted seat-tube cut? which is to reduce the impact of a square edged stress riser that a simple slot would lead to

but..folk here on about maybe making a couple of holes, then sort of filing in-between – so it could easily lead to a stress riser edge – especially nosying at it closely at the sort of scale cracks check out to get started from

“drilled a carbon SB66, took to Alps, twice. Broke wheels. Not dead.”
As another anecdote, Afan bike shop said they used to stock Yeti’s but they had a run of carbon frames breaking so they don’t stock that brand any more. It’s quite likely the frame’s overbuilt and reducing strength of a bit, like in most cases, is still safe enough…but a problem might be that it’s done blind without checking out how it’s holding together inside and there’s no basic non-destructive testing in place to see how it all behaves with repeating straining under load

“Whyte have been drilling their frames”
They make lovely looking bikes…but in the rare cases that frames break, one of the key weak spot can be just behind the head-tube, pretty much exactly where they’ve drilled a couple of holes…I’m sure they’ve done the sums – but either it’s weaker or heavier than it was before

anyway, I’m far from an expert – but I still reckon anyone with Material Science and Fracture Mechanics nouse should get a bit nervous about getting DIY busy with a drill on a bike frame

hahah – when I said ‘taken out’ I didn’t mean killed or something! I mean enough of a hit in the balls to stop them riding for a bit. Would be great it they worked as ejector seats tho : )

have you seen that Gravity Dropper singletrack review youtube? “if you do get it wrong, when you’re hovering and it hits you – it’s quite painful” – I bet!

but sure, this is all about the Reverb type ones – using similar technology as height adjustable office chairs – which likewise have never ever failed annoyingly…

“undoing my QR seat clamp dropping my seat post manually and shredding some single track”

ha – same strategy here! Dropper posts look great when they work, not so much having to ride for half a day with the saddle stubbornly stuck on low. I’ve seen a couple of riders get taken out with the seats firing back up at them too. I was reading an enthusiastic review about a fancy new bike with dropper post lever and another to lock the suspension and all I could think was, “How did that make it into the shops, given it’s impossible to turn upside down to fix a trail mechanical without knackering extra sticky up thumb switches?”

(bah humbug etc)

“Bushes are also much more compact therefore easier & simpler to design for, also requiring less material (therefore less weight and cost”

fair enough – it’d be cool if there was a way to seal them a bit better to stop grit sneaking in

“Pinch flats and burping definitely suggest you need more air in your tyres”
Ha – that first week of riding heard some creative swearing from me! I was despairing a bit really – even with a ToPeak digi pressure meter if I dropped below 45psi at the rear, riding into rocks would just pop the tube and at that sort of tyre pressure I’d just ping off stuff. Sure, finesse hopping over stuff rider-error etc – but line choice with a bit of momentum on rocky Lakes tracks isn’t alway carefully considered! Part of it a bit I guess is having spent 10yrs up-skilling on the mtb over in NZ so I was used to travelling a little quicker – but on mostly smoother trails. I’ve given up on clip-ins too, opted for dmr vaults & 510 freerides. The burping drama was the front tyre from cornering – my sense was I could run lower pressure in a tubed system without any ouchy tumbles

(for now, running 2.5 High Roller/Minnions – with a maxxis free-ride inner tube on the rear at…22psi is working alright – but kinda heavy and too fat to fit in a lot of bouncy bikes. I’ll maybe try out tubeless set up on next bike. I liked the ADvantages but – again must just be me, the XC rear and regular 2.25 on the front both failed at the sidewalls before the tread wore out – so back to sturdier kit for a bit)

“air shocks with bigger negative springs mean they actually work over small bumps”
cheers – good to hear other folks’ experience. Turner’s look decent too

“14 years ago I bought a Ti hardtail and not a full suss bike”
Good call. I wonder, for a laugh, would any racers consider riding on even a 3yr old enduro frame? On one hand it’s great that we can ride the same kit as talented professionals and in the scheme of things even at, say £1000 a year loss of always riding a fresh bouncy trail bike – it’s a cheap enough hobby. But on the other hand I kinda think we’re being taken for mugs some of the time – it’s crazy that a fancy carbon enduro bike might sell for more than a new HarleyDavidson. I’d be totally set on sticking with this Cotic BFe – I mean the excitement of riding it, sense of speed, peace-of-mind/reliability wins enough for me – but despite being staunch about it I just get a bit beat up after half a day of riding (I have a bit of Sciatica/disc-nerve pressure thing for now) so really just want a reliable, thought-through full-sus ride and felt a bit uninspired about the choices available.

Cheers for responses – I do feel better for having had a grump about the state of it all.

“Bird”
that’s a new name to me. Photos look tidy on the website.

“Orange’s range with a coil shock should keep trucking for as long as you want it to”
Yeah, I hear that from a few folk – that they like their Oranges. I bought a sub5 frame over in NewZealand in…2004 and it didn’t work out very well so I’m a bit put off the brand – part of the problem was probably so far away from customer service – but emails to them directly didn’t get much response. The swing arm just seemed really flexy – so that with pedalling the rear shock ended up being worn either side – I replaced it for a manitou coil but then I had dramas with corrosion on the top tube – I sent Orange photos but they were pretty much just ‘ooh that’s unusual’ and no further help. Then the bearing seized onto the frame – in the end needing to be attacked by the bike shop with unfriendly power tools to remove it. Meanwhile the stantions on the VanR forks marked up within 3 months of riding, the seals stopped holding oil and Fox refused to warranty – ended up having to post the forks away and pay for new stantions but they were just pants compared to how Marzochi kit used to be. All up, I was sort of put off Orange & Fox – but just unlucky experience for me I guess.

“A steel hardtail (or even rigid) bike will do the job most of the time”
yup – sort of loving my Cotic BFe for now – except I have a lower back disc thing on the go and I’m just getting beat up on the trails – hence general moan at no proper mountain bikes for sale in the shops.

“to have the bushes wear out after 4 days is pretty bad “
yeah – I thought so too! I had chats on the phone with the tuning company I got the fox coil replacement from to see if the system on that Sunn Shamann had been unusual and the response was that it’s the same as on every stock bike sold. The week up in the Lakes was fairly enthusiastic – sort of riding all daylight but nothing much gnarlier than Walna Scar / Garburn etc – plus the bike was put in a hostel shed grubby overnight – just made me think most bikes get an easier life or I was really unlucky somehow. Looking at the bush mount – there isn’t much to stop grit getting on the load bearing surfaces and I guess it’s better that wears than part of the bike/shock itself

“how much do you weigh?”
gym machine says 79kg, with 19.5% lard content

“plus size 29er”
sounds like fun! seems like motorsports sticks with big volume tyres if the surface is rocky – I’m guessing once all the fuss about letting go of fairly skinny 26″ wheels, most trail bikes will have fat rubber soon. The way I see it most folk want to have fun out riding – not always so bothered about whether a skinny xc racing snake is faster on a super-lightweight ride. As long as it climbs ok and reliable for a week away then happy days.

“No one makes something that only I want
I cant set up tubeless or air shocks properly”
fair point. I dunno if it’s particularly unusual what I want to do on a bike – I think I’d just like a sturdy ~120mm travel coil full suspension ride that I’d feel ok about taking into the mountains year round. I posted just because the difference in performance between a 2013 monarch and fox van coil was incredible – like I said instead of having to use 45+psi to avoid pinch flats, I could run 25 and hit stuff ok. I did spend a a good while faffing with set-up, with input from shock tuners but coupled with unreliability I was happy enough to switch to coil and until I twisted that frame it was brill. Ha – I managed to pop 8 spokes over time in the rear wheel too – feedback from shop was that black spokes seemed to fail more often – after swapping to DT double butted it was fine. Ok, so maybe all a bit more adventurous a life than the xc marathon bike was expecting but I’m a timid rider and not into jumping/stunts etc – plus this sunn shamann was a ~£2800 new ride or thereabouts so you’d expect it to cope with a few days in the hills.

“some US bikes make you wonder if they even have mud over there”
I hear you – this Sunn was a european version of a US design, but still 2.1″ ADvantage was about as fat a rear as it would take. I read a mag article about US bike designs coming to ride over here and they were shocked about heading out in the mud rather than wait for a sunny day!

“125-140 is about right for 90% of uk riding and riders i think.”
True that. Even a bit less – Banshee Phantom is a burly 105mm 29er and felt like the best out of test rides so far. I don’t want to fuss with locking out shock for climbing – want the bounce for traction and take rocky steeps so I figure a coil shock sub120ish would be ideal. Another thing…as much as I like the OneUp 30>42 1×10 I’m running, it’s too tall a gear for long steeps – it’s a crazy idea to spec most bikes with just single – mostly limits them to be driven to a trail-centre for a short 4hr loop.

“tubeless tyre…When set up properly it’s awesome”
Yeah I’ve read that a few times – but going back to that week in the Lakes, riding between YHAs and longer days in the hills (I stayed in Coniston/Windermere/Keswick and rode between bases with a lamp after days out on the trails) – it’s not that easy to set up with a folding mini pump is it? Might be brill with a CO2 cartridge or track pump and without getting punctures – but if it does fail – like I had a proper nasty tumble cornering when the front tyre burped off the rim, it seems to more faff than positive. I should try another go at it – the feedback here was just that surprisingly running a coil rear shock seemed to take out loads of pinch flat risks that lead to need for tubeless to begin with.

“designed to wear out”
Yeah – for racing and driving the bike to a centre, it’s mostly no dramas at all – but for a bigger day out or a few days away from a shop in the hills, it’s just a bit of a worry sometimes. I think I’d settle for bit heavier/more reliable/more£ than chase latest fashions.

“Less rolling resistance, less punctures, potentially more grip, similar weight.”
No doubt – especially on a hardtail or a light bike I figure tubeless is probably a bit necessary.

“Needle roller bearings on the shock mounts is the way to go.”
Any more info about what sort of bike/set-up? sounds cool

(soz for text wall – was just interesting posts from folk and wanted to chip in again)

Hey I don’t want to overstate my tech-skills, but I’m certain that every 3rd yr FractureMechanics paper option on a mech eng undergrad basic course would learn about the de Haviland Comet dramas – it’s a different situation with cutting square holes in a fat plane sized aluminium tube but also was a massively bigger budget project than bike frame design.

I’d be willing to bet a car that the general decision to route cables internally came from a graphic designer, rather than an engineer and that after groans there was (hopefully) a design tweak to strengthen the tubes.

It’s a tough life for aeroplanes or bike frames – built light out of stuff that doesn’t really like lots of repeated flexing – and honestly cutting a hole in a thin wall tube is adding to risk – especially if not part of original design.

Have a nosy at those lightweight drilled road racers – it was a bit trial and error – but drop-outs, brakes, cranks even were considered fair game – never the frame tubes – even tho they were steel and much more likely to bend fail rather than snap like how aluminium alloy & composite stuff breaks.

Sadly, it does happen that products fail – news to me about those Scott’s – but that would have been a reinforced hole with a thread insert rather than just like a rim without eyelet.

Also as well, most products are put together by rotating teams – not necessarily true that someone’s making call to have longer lasting kit as opposed to shiny sells well. In fact it could be cynically argued that makers want replacement new bikes sold every few years rather than making stuff durable.

Its my first day here – I was just chipping in with how I think any engineer would grimace a bit about cutting a hole into thin wall tubes – just based on what they would have heard on loop in class for a few years.

“they aren’t designed to the n’th degree”

Maybe true. But, lighter weights can be a factor in shifting units and extra drilling might be enough to cause failure in a situation an intact frame would have survived.

We’ve sort of been here before – in the context of lightweight road racing bicycles, it used to be all-go to spend evenings drilling nearly everything – but significantly the thin wall frame tubes were left intact – less weight to loose for one but also maybe to avoid risk of a tumble.

“Hope…and others forge a blank to a near net shape then CNC that. “

fair enough – but I sometimes see lots of machining done on surfaces that don’t require it, seemingly for aesthetic reasons. Didn’t mean to single out one manufacturer, but from the HOPE website about their seat clamp, “CNC machined from billet 2014 T6 aluminium” and to most customers, if it looks trick and shiny it gets bought! The fact that a forged clamp could be lighter and stronger seems to be sidestepped a bit.

(anyway, the CNC thing was just an aside about how, sadly, it not always most sensible engineering strategies that are used by wider bicycle industry)

“It’s carbon…fracture mechanics can kiss my hairy backside”

Hmm, I really wish that was true! There might be a very good reason why warranties are generally shorter for carbon composite frames/kit.

Also, drilling into a carbon composite tube could really ruin the integrity of the fibre lay-up – moving beyond the micro scale level of making a new handy spot for a crack to sprout from.

“If grit and stuff was getting into the frame on a regular basis maybe wear abrasion would be a problem.”

I admire your optimism! It might be that just the cable outer is more than capable of scratching the tube inside – and even just scratches really can hugely lower the strength of kit. Also, even internal routing done by the manufacturer isn’t competently sealed – it’s a rubber grommet so it doesn’t rattle in the shop or California at best.

I’m only posting to try and prevent an ouch – soz if I come across as just wanting to pretend I’m clever or point-score.

“I think you’ll find that in real engineering people assess the loads a component is likely to be placed under during it’s working life and use a material and manufacturing technique that produces something fit for purpose.”

OK – but, consider a stem – a CNC unit with the same structural strength as a forged unit, will just weigh more because it’s not the optimum strength for weight solution. Sure it looks trick and sells well, but it’s inefficient component design. Machining is generally used to face/finish, for small runs or tricky shaped stuff, but it mostly results in components with poor structural properties compared to comparable alternative techniques.

“Do you think you need to be a chartered engineer to be a frame builder then?”

I didn’t mean to come across as a know-it-all, and I’m well aware of frame-building tradition that shares more in common with artistic black-smithery than book-learning, but there’s a few subtle concepts that maybe don’t make common sense to begin with – like:

1. Temperature stuff – metal looks pretty robust stuff, but the mechanical properties can be radically altered according to heat treatment – so getting busy with welding kit might really ruin the strength of the tubes without a bit of tech nouse informing it all.

2. Work hardening – I’ve had a browse through books by contemporary frame builders and it is fully frightening watching them bend a fork and then think they can unbend it back a bit into shape with no impact on strength.

3. Fracture mechanics – (soz for geek) but do you remember those glass rods for stirring beakers with in chemistry class? Ok so in a test machine, try bending them until they snap – then dunk them in hydrofluoric acid for a bit to remove surface scratches etc and try bending them again – serious orders of magnitude stronger before they snap! Similarly rubbing a gear cable away at the inside of a frame WILL have majorly weakening effect on it.

4. CNC kit is mostly crap. Sorry HOPE/Chris King etc – all hype over substance. Compared with a forged compenent, the internal stress distibution of a CNC component is way less than optimum. In real engineering, CNC is used to make a prototype and then use a different technique to make a robust item.

less $ for makers obviously…

But, arguably a manufacturer that made kit that lasts with just renewing bits that wear out would sell well too.

“The manufacturers design and build the frames taking in to account where they want to put holes and how these holes will affect the frame”

Well…not necessarily – I’d be willing to bet the engineers face-palmed the designers decision to cut open new Specialized down tubes to make a box for snacks. Already, there’s such painfully bad design from other makers that results in internal routing rubbing against carbon steerers in forks!

PLEASE, LEAVE YOUR CABLES OUTSIDE & USE A FRAME PROTECTOR STICKY rather than get busy with a drill/file for a clean look and cause a hurty tumble and red-face on the trails

“don’t make a round hole”

That de Havilland Comet mentioned is a sort of famous fracture mechanics disaster case. Airliners that crashed repeatedly because they had square windows in an aluminium body – on account of the sharp edges resulting in stress risers and a start point for a crack and resultant fracture. So, I would really strongly caution against any sort of a hole – on a micro scale, a drill or filling away can leave all sorts of jagged edges that honestly would drastically reduce the strength of the frame and cause it to fail (crash – ouch etc) unexpectedly.

“bottle boss”
Sure there’s a nut thread – which at a bare minimum would protect tube in similar way to why eyelet rims are stronger than without – but often the fitting is such that the threaded part becomes a structural part of the hole and would serve to limit crack propagation.

“Cy”
A bike maker with a mechanical engineering degree and “I’m not going to promise it doesn’t break in half” is a good honest call.

de Havilland Comet?

Have another look at the bottle boss holes…see if they’re just a hole in a tube or has some reinforcing material been added…

From a structural integrity perspective, yes. Also, internal routing means that cable wear becomes invisible and could lead to catastrophic failure without warning.

I think the main problem is that designers are not necessary very aware of fracture mechanics or stress risers and more concerned with a ‘clean’ look to sell more units.

As a mechanical engineering graduate, can I just chip in with the input that drilling holes in a frame is a really bad idea.