You measure BB height sagged? May I ask why?

You measure BB height sagged? May I ask why?

When I ride my bike the fork is sagged 😆

I’ve measured it both ways but since I was trying to understand how the geometry (BB height) changes with travel I’ve found it makes more sense to go by the sagged measurements. I’ve also found that using a very soft fork to “over-sag” a frame makes it ride like shite so giving the sag figure as 25% (or 30% whatever) makes sense (to me anyway).

It helped me understand what I liked about a frame I had but broke, what I didn’t like about it’s replacement, what I wanted and liked in the next one, and what I really wanted and like in the one I replaced that one with (this could go on a bit).

I sometimes have the forks on my trailstar out to 140mm but it seems to ride better with them at 120 ish for general riding about then wound al the way in for jumping. Think its a bit to do with the divey forks but also bb height.

What a load of cock this thread is. Basically some people like some bikes others don’t. Why argue about it? I rode for a short time a 29erm for the first time the other day. Granted it was a bloody fancy titanium IF frame. But it was really good I got up a climb easier than I ever had before I really liked it and would like to try more. I can even see myself owning one. However when I got back on my BFe I knew that I would never swap it for a 29er. My two bikes are perfect for my riding, I can see a 29 being useful if i did longer more xc rides but I don’t.

I can honestly say that riding your bfe has confirmed the fact to me that 26″ wheels suck , I have a set of 29er 140mm all ready to go on my new build 😀

I just realised that I misread your post. I thought your LTHT was a BFe, which does not have a low BB at 12.25″ (I have no idea at what fork length that is measured – you’d need to ask Cy).

I wouldn’t consider a sagged BB height at 12″ low either. Very few LTHTs would have what I’d consider a low BB height. I saw that chumba stating 11.5″ recently and believe the NS Surge does as well, but again I have no idea what fork length they are measured at.

Measuring unsagged makes much more sense to me.

As soon as I read a geometry chart of a sagged bike my brain automatically converts the fork lenght to compensate. Ie. 160 @ 25% = 120 and it’s a PITA if I’m honest.
While riding, sag is not a static measurement (or even an accurate average measurement) and I don’t run anywhere near 25% sag so I have to work with static unsagged numbers before the rest makes sense.

Would you measure full sus geometry sagged too?
That would be a massive headache for me as I run around 15-20% sag front and 35-45% rear but know what static geometry I like/suits me.

GW – my hmmmm response is nothing sinister! Your choice of bike is an interesting answer to that perennial question of shorter travel forks but with trail bike geometry rather than XC geo. I could never ride an STP without a 600mm seatpost and most of it stuck out of the seat-tube though! I like aluminium so long as manufacturers actually use it’s avantages and make a lighter frame. There’s lots of alu hardtail frames that are so overbuilt you may as well get something steel.

So, light alu frame with slacker than XC geometry for sub-120mm forks – anyone? I can think of Whyte but that’s about it. The Ragley mmmBop was a claimed 3.5 pounds, but obviously for longer forks and clearly didn’t sell for whatever reason.

How tall are you and what inside leg?

5′ 10 and a bit (the bit is very important!) and a 33 inside leg if you believe M&S.

Currently run a medium Chameleon with U-Turn Pikes at 100 to 120mm mostly but even then the seat angle is too slack. There must be something that’s as good fun down but less compromised on the way back up.

The 600mm seatpost was an overexaggeration, but I’d still need a 450mm at full stretch which is a big old lever.

using a very soft fork to “over-sag” a frame makes it ride like shite

Yeah with too low a spring rate, it starts to become over-active under compression which upsets balance. But you can compensate to some extent by increasing compression damping if your fork has this feature.

That doesn’t avoid the problem of the fork fully extending when climbing which feels horrible, unless it has a lock-down feature. I’m quite interested in the Sektor Dual-position coil fork because you can squash it between 150 to 110mm and then lock-out using the compression damper while riding (poplock). I think this is more convenient than the u-turn idea which you cant practically adjust without getting your weight off the fork and then there is all that winding. And the DP coil is much lighter too. Anyone got one yet?

Sometimes it just seems simpler to use a shorter travel fork. 🙂

I think this is more convenient than the u-turn idea which you cant practically adjust without getting your weight off the fork and then there is all that winding.

I can wind/unwind both my pikes and lyrics whilst on the go no problem?

No idea what the geo is on my crush but it is good fun….

Thanks for the public service announcement.

I’d better get working on one of those 29’er things!

Rickos, do you have a straight seat post and/or have any forward space on the saddle rails? There’s a good few degrees of actual seat tube angle adjustment there. Or you could stand uphill? 😉

If I were selling HT bikes I’d provide geometry charts for various axle-crown lengths, equating to various fork travels both static and with various amounts of sag. Unsagged isn’t very useful for comparing to FS or rigid frames but sag % preference is quite variable. My HT’s BB is just above 13″ – on the higher side which I like for the ground clearance – for nice cornering, bend the legs to get your CoG down.

I can wind/unwind both my pikes and lyrics whilst on the go no problem?

You have great balance!

chief – running a Joplin but with the saddle rammed forward. TBH the frame is too small (it’s an old medium with the horizontal dropouts), but is a lot of fun when stood up.

You have great balance!

Thanks. Although I have ridden into the hedge before not looking where I was going.

Easier on the lyrics than pikes as the adjuster is biggerer.

Rick – are you ever happy with a bike?

Rickos – STPs came in 2 sizes, (I ride the smaller as I like shory DJ style bikes) the larger of the two is an inch longer with a 15″seat tube.
@5’11” and 32″ inside leg (never worn M&S tho) I just manage full pedalling ext (for flats) woith a 410 post. I do however run it slammed mist of the time with the saddle tilted back DJ style – thus actually helps with climbing too as at full ext I can perch on the nose to ge better ext and weight forward ffor steeper climbs without having to stand up. I will always put up with a compromised set-up for XC to allow my bike to jump well and descend nicely tho.

Jim – very happy with my Stumpy EVO. Just need to sort a good hardtail and then I won’t know what to do with myself!

GE – Ta. I’ll have a butchers at that then. I assume frame is sub 4 pounds.

Nope, it’s a wee bit over 4. It is still a DJ frame afterall.

If a Zaskar was good enough for Steve Peat, it’s good enough for me…

Just built up a pace rc305 with 150 revs.
So if somethings going to die it,s probably going to be me when the frame snaps going full pelt down a rocky section. 😆

Mike. Make sure it has the following ….

Conehead.
Iscg mounts.
31.6mm seat tube dropper compatible.
Full gear outer routing.

I’ll happily test one for you if you decide to get some protos…… 👿

This is a very silly thread. Bikes are ace, some people like different bikes from other people.

buzz-lightyear – Member

You have great balance!

It’s incredibly easy 😕 Can you not ride one handed? Adjsuting a u-turn on the move is about as complicated as taking a bottle out of a cage.

It’s incredibly easy Can you not ride one handed? Adjsuting a u-turn on the move is about as complicated as taking a bottle out of a cage.

Not in my experience and I can only really ride one handed when its smooth and level. 12 twists from longest to shortest while reaching down over the fork, holding on with the other hand while pedalling and bouncing off roots is feasible. But going the other way the knob resists twisting while the fork is weighted. No?

Makes no significant difference which way you’re going but why would you attempt it while “bouncing off roots”? You wouldn’t try and have a drink or adjust your zips in the middle of a tricky section, or adjust your fork, you do it in the gaps.