Gravel bike gearing help please

Hi,

I’ve just bought a transition rapture cross bike off a mate to use as a gravel bike- I’m excited to see some new trails!

Its come with
-10 speed 105 shifters- St-5600
-Tiagra rear mech, Shimano RD 4500 / SS – 9 Speed it think
-38 tooth narrow wide ring

I have a hope pro 2 hub arriving to build into some new rims

I’d like to run a 10 speed deore 11-46 10 speed cassette and rear mech. Can I do that with the current shifters?

Also will that 38 11-46 be a decent spread of gears for a bike that will always end up doing significant road mileage before getting to any off road stuff? My road bike is on 50-34 chain rings and a 12-30 cassette and I’m out the saddle in the lowest gear on some roads.

Cheers!
Martin

Jealous of that, looked for one for ages but gave up

Anyway I run my Cotic 38×11-36 10 speed and that rarely spins out on the flat and can climb anything. 10 speed road shifter means road rear mech but a tiagra will do 11-36 easily and probably 11-42, which would mean better spread and less jumps between gears

I’m running 38t N/W with an 11-34 at the minute which is just fine, I have an 11-36 that’s probably going on in summer, I’m using an old 9speed SLX mech with 10 speedshifter… TBH unless you’re going to be seriously loaded up I reckon an 11-40 (maybe 42) cassette should be plenty with a 38t ring on a gravel bike (YMMV)

The 5600 shifter should be fine, but you’ll need either an 9speed MTB mech (to match the cable pull ratio) or something like a road link To accommodate bigger cassettes…

Also will that 38 11-46 be a decent spread of gears for a bike that will always end up doing significant road mileage before getting to any off road stuff?

No idea about the other stuff, but my experience says no.

I’ve 42 11-42 on mine, and run out of gearing at about 35-37mph.

But on 1-to-1 can get up pretty much anything I need to, on or off road.

38t is about right on a gravel bike I’ve found – a 38×11 top gives you a big enough gear for well over 20mph at a decent spin and that’s fast enough for anyone on a chunky steel gravel bike.

Then think about what bottom gear you need, I’ve run 11-40 in the past and found it about right, not sure of they do a ten speed 11-40 casette though.

on a 650+ and fat tyres
42 chainring
10 – 42 up back
can sit in the fastest gear on the flat and keep a decent cadence downhill but to be honest i bottle it around 30mph, and flat bars don’t lend itself to the best aero
I don’t take the bike where my proper MTB’s go so the 42×42 gets me up everything i need it to, literally commuting, gravel/mud shortcuts and blasts out after work from home
I feel 38×11 might get used quite regularly

The top gear thing: I would spend barely any time doing over 30 on roads, of you feel you need to pedal for a few mph at these speeds fair enough, but I wouldn’t bother lots of extra expense or other compromise to be able to do so. Freewheeling isn’t so bad.

I was 42*11-42 (1:1) and found it a little hard on steep off-road climbs (and I’m a singlespeeder).

Briefly tried 42*11-46 just because I had the cassette, but settled on 38*11-42 which will get me up most stuff with bikepacking stuff.

Thanks @chrishc777

It is unlikely to get laden with kit. Perhaps one bike packing trip this year, perhaps.

@intheborders

I’ve 42 11-42 on mine, and run out of gearing at about 35-37mph.

I’ll just be freewheeling at the speed on gravel- unless you mean 35mph on the flat! In which case I tip my hat to you and will never take your kom’s

big enough gear for well over 20mph at a decent spin and that’s fast enough for anyone on a chunky steel gravel bike.

My mate sold it to me mostly because it’s heavy 🙂

I’ll try a road link and see how that goes

My Camino is 1 x 11

38t on the front and 11/42 on the back end, which shortly will be a 38t oval (absolute black) and an e-thirteen 9-46 on the back.

That should do me for a while

I’ll just be freewheeling at the speed on gravel- unless you mean 35mph on the flat! In which case I tip my hat to you and will never take your kom’s

No, you said you’d be doing lots of road inbetween. I live in a hilly area so the majority of roads are either a climb or a descent.

You could put a 10/11 spd MTB rear. Mech on with those shifters if you fit a Tanpan 10.

https://www.wolftoothcomponents.com/products/tanpan

Im on 10 speed 11 – 36 with a 38 chainring. Its fine on the hills inc a couple of Cat 3 Climbs. I’ve never wanted to go so fast i spin out on the flat as its just not that kind of bike (i have a proper road bike for that type of behaviour).

run out of gearing at about 35-37mph.

Depends a bit on location, I would rarely be peddling at that speed, down here in the south the descents are rarely that pedal able, more open road peddly descents up north..

No idea how the ratio’s stack up but my gravel bike with slicks is 48:11 biggest gear and I have never wanted more on slicks in group rides. My road bike has 53:11 and I rarely use that gear.

44 front and 11-42 on the back gets me up anything up to a 25% gradient and only spins out on the faster road descents. Having said that though I’m about to change the front to a 42 as it’ll be a bit better off-road.

Some OEM 105 5600 series LH shifters are actually 5603s, allowing you to fit a triple chainset. Check under the hood covers for 5603 or disconnect the front cable and count the clicks. Discounted Tiagra 10 speed triple 30/39/50 chainsets are still available and if paired with a suitable 10 speed road triple front mech would give you a decent gear range without fitting a rear dinner plate cassette or mtb mech.

My Camino is 1 x 11. 38t on the front and 11/42 on the back end

Same.

38×11 sees me spinning out on road downhills. There’s one section on my commute where this is mildly annoying.
38×42 feels pretty easy to me, I feel like I could manage a harder gear just fine on anything I’m likely to ride.

Given free choice, I’d probably go for 40t or 42t, but the (Oilslick B) ) chainring I’ve got is only available in 38t and it’s worth it for how rad it looks.

Thanks again!

I’ve gone for a road link and an 11-36 cassette.

I’ll probably be cursing the lack of low gears, but it will do for an experiment for now.

If the cassette doesn’t work out, I can always shift it over to my road bike as that is also 10 speed, but a double.

@intheborders, sorry if I’ve caused offence, it wasn’t intended

Thanks again for the advice.

I went for the mech extender and an 11-36 cassette.

First ride out and the shifting was perfect.

The ride was pretty flat. There was plenty of top end for a 12kg bike with some aggressive cross tyres on the road. There was one hill where I would have loved a few lower gears.

The bike has been built with some heavy mbt wheels, mtb tubes and wire bead tyres so I’m sure the weight will come down a bit.