Help me spec my budget gravel bike

I’ve got hold of a very reasonably priced Boardman ADV 8.9, which needs a bit of work and which I have the opportunity to spec to my taste. I’d value some opinions and product ideas, if you’d be so kind.

Use case
I have actual gravel tracks from the top of my road and I expect to use this bike for 70/30 off/on road – towpaths, farm tracks, country park, moorland paths, singletrack, cobbles and the odd techy bit at Rivington.

Gears
It came with GRX 400 2×10 gears (Tiagra 4700 GS rear mech), but the rear shifting doesn’t work, so I’m setting it up 1×10.
I’ve ordered an Ultegra BB and GRX 600 single chainset with 40t ring, to replace the very tired FSA stock parts. Initially I’ll run this with the 11-36t cassette, but that’s probably borked anyway – so how wide a range cassette can I use with that mech? Would 11-42t be viable with a single ring?
Deore 4100 cassette looks good value and a decent weight? Or Sunrace?
If not, what are my options for replacement mechs? MTB ones apparently have a different pull ratio? So just the GRX mech?

Tyres
It’s got 38mm Marathons fitted at the mo, which look like they’ll be fine on farm tracks but I might want something a bit more toothy, as I’ll mainly be riding off road.
What gravel tyres are good for the riding specified above?
How wide dare I go? 45mm will probably fit, but will that compromise my options for..

Guards
Related to the above, I’ll probably want mudhugger-style guards both ends. What have you got and how’s it been?

Thanks in advance, gravel fwends.

🙂

I seem to recall that era of Tigra having a unique pull ratio. Might be worth checking on a Shimano compatibility sheet before buying new parts. I guess you’re safe of you stick with 4700 kit though.

Schwalbe Smart Sam 700x40c (actually stamped 700×42 on the sidewall), not sexy, but at £16 each they’re a lot better than they have any right being. Or Vittoria Terrano Mid/Wet combo if you’re feeling flush.

I seem to recall that era of Tigra having a unique pull ratio. Might be worth checking on a Shimano compatibility sheet before buying new parts. I guess you’re safe of you stick with 4700 kit though.

There was something odd about it, does it use 11s road mechs or something.

Have a look at j-tech shiftmates, there might be something in their list that’ll let your shifters work with an MTB derailleur which would be the ideal option.

It came with GRX 400 2×10 gears (Tiagra 4700 GS rear mech), but the rear shifting doesn’t work, so I’m setting it up 1×10.

I would sort that before buying new kit, if I was on a budget…

(Mine is also 2×10 Tiagra, and it is just not low enough geared for either off-road or Highland inclines…. I’m swapping the 2x cranks to Spa Cycles 2x with smaller chainrings when current ones wear out, job jobbed for £70)

That generation of tiagra (I think) uses (road) 11 speed cable pull so presumably the GRX does too. So any roadie 11s rear mech that matches the (10s) cassette you want to run. Grx812 is the official one for using with mtb cassettes but not cheap!

I ran a short cage 105 rear mech with 11-36 and it was fine, probably pushing it to go much bigger!

Mudguards- mudhugger gravel/cross front has been good here. Not full coverage but gets the worst. I’ve found this pretty good for rear- Cheap mudguard.

Just make sure you tape the seatstays with something tough and use the rubber pad.

Yes, the GRX400 10sp shifter has the same pull ratio as 11sp Shimano road (and 4700 Tiagra).

Schwalbe Smart Sam 700x40c

They look really good, they only seem to be wire bead though, I know I said budget but I could spring for folding tyres. £50-60 /pair maybe?

Have a look at j-tech shiftmates

These look clever, but I might as well get the GRX mech by the time I buy one of them and an 11sp MTB mech to go with?

I would sort that before buying new kit, if I was on a budget…

It’s a non-serviceable part that’s broken, and the chainrings look toasted anyway, so switching to 1×10 seems the most economical solution.

Mudguards- mudhugger gravel/cross front has been good here. Not full coverage but gets the worst. I’ve found this pretty good for rear- Cheap mudguard.

Just make sure you tape the seatstays with something tough and use the rubber pad.

Good stuff, ta. I always use mastic tape under my mudguard zipties.

I’ve the wolftooth shiftmate equivalent in both 10 and 11s and they’ve been solid for years. At the time there wasn’t a purpose built mech.

One thing I’d looked at as the 10s stuff is very much wearing (worn) out is sticking a wide range mech and the microshift 11-48 cassette on. They’re not supposed to be cross compatible but I’ve used 11s road shifters, tanpan, 10s mech and cassette happily. Tolerances might go the wrong way but I reckon worth a go.

Edit- weirdly delayed double post

They look really good, they only seem to be wire bead though, I know I said budget but I could spring for folding tyres. £50-60 /pair maybe?

Pre-tubeless, I did the Three Peaks CX a couple of times using Schwalbe Smart Sam tyres, they were really good.

Unless you are planning on going tubeless, you’re honestly not going to find any better tyres. Fast rolling, grippy, cheap, not that heavy. Get them, spend the savings on other bits!

Pretty much what crazy legs said about them, and I’ll add that they work perfectly tubeless too.

OK, OK, I’ll get the Smart Sams 😀

One thing I’d looked at as the 10s stuff is very much wearing (worn) out is sticking a wide range mech and the microshift 11-48 cassette on.

I’m not sure I’d need the extra range? Will a 40t chainring and 11-42t cassette not be adequate? Not planning on doing any loaded riding.

1-1(ish) is plenty low enough for almost everything so 40-42 would be fine. I think my lowest is 34-28 as I’m limited to road ratios and that’s manageable just at a lower than optimal cadence and the odd bit of having to stand up and grunt.

I’d go GRX 400 2 x 10. I have GRX 600 1 x 11 and although it is perfect for >90% of my riding, the gears are not quite low enough for proper long big steep climbs. It’ll get up them but will be a grind instead of nice spin.

Tyres, as always I’d go for something Vittoria Terreno. Mix at 38mm should do the trick, they measure 40mm on my rims which for me is a great compromise of comfort, speed and grip. As gravel/cross tyres are narrower than mountain bike tyres, you really don’t need as much tread. The tyres seem to cut through the mud better. I’m actually still riding on Schwalbe G-One Bite which are excellent tyres despite their minimal tread, not quite as grippy at the Terreno Mix though.

As for guards, I’d only bother with an ass saver type, as the tyres don’t pick up as much mud as a mountain bike tyre you don’t get as filthy. Front guards can also cause toe-overlap issues which isn’t ideal when riding off-road. Plus the dreaded rubbing noise and rattles would drive me to despair, some guards are quieter than others but they all rub when you ride off rod in the wet and mud.

I’m not sure I’d need the extra range?

Probably not, I did years on just 40 11-36 and find 10-42 to be suitable for almost all situations, but it’s always nice to know you have options

I’ve ordered the Smart Sam 700x42s now 🙂

As for guards, I’d only bother with an ass saver type

I’ve got one of those kicking round somewhere that I never used, will try that in the first instance, ta.

I can’t go 2×10 without a new brifter, so gotta be 1x.

Riding will mainly be flat-ish or rolling though.

I’m sure you’ll love the 1 x gears for simplicity, with a double it can be tiresome changing the front and rear to get just the right ratio on rolling terrain. sounds like you’ve made the right choice,

If you want to go 2x but don’t wanna pony up for a new brifter, consider a bar end shifter, light, cheap, no compatibility issues.

Thanks, but I think 1x will be right for me anyway.

Oddly I’m more excited about this than my last boutique full-sus build. Probably ‘cos this will enable a different type of riding, rather than just the same but with a different frame.

Probably ‘cos this will enable a different type of riding, rather than just the same but with a different frame.

So this. Totally different rides.
And all the better for it.

I’m running 1×10: 38t ring with 11-36 cassette (with whacky shifters and an old MTB mech).

I think the trick with 1x Gravel bikes is choosing an appropriate N/W ring as much as picking a cassette; the trouble is (IMO) bravado seems to kick in and people have to order a 40,42t or larger ring and then end up needing a 40t or 42t Cassette to give them an appropriately low-ish ratio for off-road climbing, but it’s not a road bike…

Go a bit smaller on the chainring, say 38t or even 36t(?) and you can run a nice cheap (possibly lighter) 11-36 cassette and achieve a usable climbing ratio, the compromise being your tallest gear isn’t huge. But 38-11 is still fine for chopping along on the flat you might ‘spin out’ on the odd descent or flat road, but as you said in the OP the Use case is 70/30 with more off-road. Gear for off-road trundling, not on-road speed.

The other thing to look at is the relative cost of chainrings, I happen to be running 104mm BCD, 4 arm cranks and I know I can get cheap N/W rings for a tenner, all the way from 30t up to 44t+ probably if I want to try a different one. You’ve probably got choices with a GRX crank now (110mm BCD Asymmetric?) down to 34t(?) But that old FSA crank is probably 110 BCD, 5 arm? bet there’s more cheap N/W available rings for it than the newer shimano standard.

As for Mech cable pull, 4700 should work with GRX 400.
IIRC 4600 was old 1.7-1 cable pull, 4700 and later was 1.4-1 (like all current 11 speed road groups, and all flavours of GRX) what exactly is goosed on the rear shifting? could just need fresh cables and some TLC, is the hanger bent or something more terminal?.

If you ultimately end up needing to go for a wider range cassette, the sensible thing to get would probably be to just get a GRX mech as well; they’re intended to work with wider cassettes and 1.4-1 pull shifters. Shimano Road mechs of most generations can do a 32t sprocket, some will manage 36t but not all of them, and stretching it further to a 42t sprocket will mean road links and other shenanigans, it’s probably worth buying the newer product intended for that application.

I’ve just a built a new gravel bike, and couldn’t get my head round how 1x would work for me. I don’t quite get the popularity of it on this type of bike. They have the potential to be so versatile, but running 1x just seems to limit that.

I want to credit card cycle tour on it this weekend
Commute on it 2 / 3 days a week
Maybe race CX on it
Use it on the turbo for Zwift racing
Use it for depths of winter chain gangs
Ride with the family on bridleways
Do the Dirty Reiver next year

A 1x setup would make it fairly useless for a few of those things… Unless I had like a 48t chainring and cassette.

If you ultimately end up needing to go for a wider range cassette, the sensible thing to get would probably be to just get a GRX mech as well; they’re intended to work with wider cassettes and 1.4-1 pull shifters.

This is what I’m thinking.

And if I later upgrade to GRX600 controls it’ll still be the right choice

A 1x setup would make it fairly useless for a few of those things

Totally get that, and I don’t wanna do any of those things 😀

Got a year-round road bike, don’t Zwift, not racing CX, don’t commute and highly unlikely to go touring.

Just want something to spin around the local gravel, towpaths and moors for an hour or three.

1x should be perfect

I want to credit card cycle tour on it this weekend
Commute on it 2 / 3 days a week
Maybe race CX on it
Use it on the turbo for Zwift racing
Use it for depths of winter chain gangs
Ride with the family on bridleways
Do the Dirty Reiver next year

So 2 or 3 bikes in one then really?
Yeah obviously if you want one bike to do all of that you probably are going to benefit from 2x (or at least a couple of interchangeable chainring/Cassette options if you opt for 1x) and at least a couple of pairs of tyres too.

My gravel bike currently doubles up as a CX race bike (with a wheel change), but I have a cheap, basic 1×9 road bike (40t/11-34, 25mm road tyres with guards) that serves as commuter/winter road bike, and a nicer ‘summer’ road bike that is 2x…

TBH I suspect most “gravel bikes” actually end up primarily used as weekday road commuters/pub bikes much like the one the OP has obviously acquired; Owners bung a set of marathons on, disc brakes naturally suit grotty weather, maybe add a pannier rack.

Narrower use cases can benefit from simpler 1x setups though.

TBH I suspect most “gravel bikes” actually end up primarily used as weekday road commuters/pub bikes much like the one the OP has obviously acquired

Very perceptive.

It’s been used as a commuter and it’s showing it, well overdue a service. That did mean it was very cheap though.

🙂

Debut ride this eve, really enjoyed it.

Here’s a pic…
https://www.instagram.com/p/Cj6FjHDsqVW/

Thank god that changing the pads and discs has fixed the terrible screeching the brakes were making. They feel really nice now.

The 1x chainset seems a sound choice. I could live with the 11-36 cassette for a bit, but I’m gonna need a clutched mech to keep the chain on anyway – so I’ll order a GRX 812 mech and Deore 11-42t cassette tomorrow.

That’ll take me to about £560 spent, which I’m quite pleased with. My cheapest proper bike for a looooong while.

I don’t quite get the popularity of it on this type of bike. They have the potential to be so versatile, but running 1x just seems to limit that.

They are versatile in that they can ride a bit of road and a lot of off road. They won’r replace your fast road bike, your tt bike, your MTB etc,. but they are not supposed to.
When I used gears I was happy on a 40t chainring with an 11 – 32 cassette. Got me up all the hills as 40/32 is very low to someone who hasn’t used gears for most of the last 20 years yet still let me ride fast enough with 40/11.

So it’s getting a bit more expensive in that the brake calipers appear to be leaky AF making the brakes honk like mad again. Which I’ve now discovered is a known Shimano issue. I must have been very lucky with their brakes up to now.

The calipers appear to be very well used anyway, so I’ve ordered replacement GRX 400 ones and the seller is going to make a small contribution to the cost, which is much appreciated.

Bit annoying that I can’t really ride it for a while, but still been planning some local jaunts to look forward to when it is up and running.

They are versatile in that they can ride a bit of road and a lot of off road. They won’r replace your fast road bike, your tt bike, your MTB etc,. but they are not supposed to.

Ironic for someone who tells us at every opportunity they’ve replaced their MTB with a track bike 😉

Finally got this thing fully operational, having fitted:

New calipers & rotors
New chainset & BB
New rear mech
New cassette & chain
New tyres

Total cost about £620 now I think, bit more than expected but not bad for the spec, what do you reckon?

It weighs in about 10.5kg without pedals (11kg with Time Atac Freeriders – the only clipless pedals I have) and I think it looks great and – more importantly – rides very well.

Really looking forward to a proper ride on it.

🙂