Gravel geometry/fit?

[dvancleve]

My next bike will almost certainly be an all-road/gravel bike with hydro discs. How do you folks size a gravel bike, pretty much the same as your preferred road bikes? I have happily ridden on some pretty rough roads (paved and dirt) and done some "under-biking" on my Rivendell with good results, so it seems like a road bike fit would be fine.

OTOH, I can also see how more top tube and shorter stem might be good for taking weight off the front wheel. The Lauf has a pretty long TT, at least in my size, for this reason. I am intrigued by the Slate, but what I would consider my road size (M) has a shorter TT & HT than some of my road bikes but the next size up is L with a 57cm TT. With a 9CM stem, that would work and the standover would still be okay, don't think if myself as riding a size L frame though...

Thanks, Doug

[John H.]

I think in most cases you want the same size as your road bike.

1.) Same size but with the ability to shorten reach and run a bit higher. Maybe 1cm for each.

2.) must consider reach to hoods more than reach to center of stem. Hydraulics levers are bigger and longer- Need to account for this.

3.) Focus on stack/reach more than head tube length on the gravel bike. Gravel bike will have much more stack due to taller fork. You can have a gravel bike with a fairly short head tube but decent stack. It is all about putting the bars where you want them.

4.) Lastly- You don't want to take weight off the front wheel, but gravel bikes tend to have a longer front center as it is. Depending on your fit, riding style and preferred terrain you may want the longer front center for more clearance with the from foot.
I have to slightly watch my foot on switchbacks. 54cm bike, size 45 feet, cleats in a rearward position.

[Jgrooms]

ok, what are the diffs between 'gravel' and 'cx' bikes

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[booglebug]

Originally Posted by John H.

I think in most cases you want the same size as your road bike.

1.) Same size but with the ability to shorten reach and run a bit higher. Maybe 1cm for each.

2.) must consider reach to hoods more than reach to center of stem. Hydraulics levers are bigger and longer- Need to account for this.

3.) Focus on stack/reach more than head tube length on the gravel bike. Gravel bike will have much more stack due to taller fork. You can have a gravel bike with a fairly short head tube but decent stack. It is all about putting the bars where you want them.

4.) Lastly- You don't want to take weight off the front wheel, but gravel bikes tend to have a longer front center as it is. Depending on your fit, riding style and preferred terrain you may want the longer front center for more clearance with the from foot.
I have to slightly watch my foot on switchbacks. 54cm bike, size 45 feet, cleats in a rearward position.

Agree, especially #4. On a steep enough climb you can"t get out of the saddle so you want some weight on the front wheel.

[charliedid]

Originally Posted by booglebug

Agree, especially #4. On a steep enough climb you can"t get out of the saddle so you want some weight on the front wheel.

I'll join the choir on this.

[dvancleve]

Thanks Folks.

Just to clarify, I meant probably no 120+ stems on gravel bikes more than little weight on the front wheel...

Doug

[wallymann]

i tend to ride on nicer gravel, so i can get away with the exact same aggressive position as my road bike, same saddle height/setback + same saddle-to-bar reach/drop. with my allrounder's geo i ended up with a 12cm stem instead of my normal 13cm, having that slightly longer front center makes sense.

i think if you tend to ride on rougher/unimproved gravel, you might benefit from having a shorter/higher handlebar compared to a pure road position.

[owly]

Agree with John H.

For me it would be around 10mm shorter reach, and about 15-20max taller stack. Just have to check the frame geo for that front-to-centre for any toe overlap. Even more so if running 700x35+

[ergott]

I run the same fit on all my road bikes.

[d_douglas]

I have a three year old desalvo CX bike that is mannered like a gravel road type bike in my opinion. I put hydro Shimano on the bike and the long hoods made me have to shorten the stem from 110 to 90mm. It was a big change but it converted it from a road feel to a MTB feel when riding (especially with 46cm bar)

That said, I woill probably look out for a 100mm stem to get it back to feeling like the nice balanced all rounder that it is.

With the 90mm stem, I raced a technical course and it turned out to be a great choice...

[yashcha]

I did not realize the length of the hydro shifters would make that much of a difference. I usually ride a 53.5cm tt with a 12cm stem on my road bike, but for my all roads I specced a 54.5cm tt with a 11cm. Knowing this detail about the shifters, I may have to go down to a 10cm.

Originally Posted by d_douglas

I have a three year old desalvo CX bike that is mannered like a gravel road type bike in my opinion. I put hydro Shimano on the bike and the long hoods made me have to shorten the stem from 110 to 90mm. It was a big change but it converted it from a road feel to a MTB feel when riding (especially with 46cm bar)

That said, I woill probably look out for a 100mm stem to get it back to feeling like the nice balanced all rounder that it is.

With the 90mm stem, I raced a technical course and it turned out to be a great choice...

[bigbill]

I've got a Coconino and Garro used his standard measurement sheet and measurements from my road bikes. The top tube and stem are the same as my road bikes, 58 and 120. I've got good front/rear balance and the slack headtube makes for a long wheelbase and seated climbs are good. One thing to consider is that if you use some Salsa bars, the reach will be shorter, but if you go wider it works out.

[Clancy]

Originally Posted by ergott

I run the same fit on all my road bikes.

Run the same fit on all my road bikes.

My gravel bike is not a road bike.

I run my gravel bike with the reach shorter and bars higher.

[ergott]

Originally Posted by Clancy

Run the same fit on all my road bikes.

My gravel bike is not a road bike.

I run my gravel bike with the reach shorter and bars higher.

I consider my "gravel" bike a road bike. They are roads after all.

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[wallymann]

Originally Posted by Clancy

Run the same fit on all my road bikes.

I run my gravel bike with the reach shorter and bars higher.

how can that be? those 2 statements contradict. saddle-to-handlebar reach and drop are essential parts of the fit equation.