MTB Fit (bar and stem choice)

[ColonelJLloyd]

Expecting my hardtail frame next week and the last pieces of the build are the cockpit components. I feel I have my road fit pretty well down.

I'm going to be using the Thomson Trail bar. 750mm wide, 12mm rise, 6d backsweep.

Current road bike
Stack: 603mm
Reach: 378mm (57cm TT)
Stem: 0d 100mm
Bar: 120mm reach/130mm drop (randonneur bend)

MTB frame (Lynskey Ridgeline 29SL size L)
Stack: 651mm
Reach: 423mm

If I add some figures to get a general effective "reach" of where I put my hands (assuming same saddle setback for both frames) then I get something like 598mm (378+100+120) for the road bike.

Doesn't seem that's very useful for choosing a MTB stem as I don't know how to account for large disparity in handlebar width and the fact that MTB position is generally more upright.

I realize this is something that you can't just do on paper and it's a trial and error kinda thing, the human body is adaptable, and on and on. But where should I (where would you) start? 70mm 0d stem? Longer? Shorter?

Thanks!

[p nut]

Doesn't "reach" mean distance from center of (horizontal) bar to the front end of the drops? Unless you are holding the bar at the end (which shouldn't be the case on a rando bar), your "reach" is going to be much shorter.

I think you're over-thinking it. :) Go with an 80mm stem and see how it works. I think that's a good middle ground, and where I typically start. I believe I have 80mm and 90mm stems you can borrow, if you want to test it out. Shouldn't be much more than $5 for postage.

[christian]

I have a 6cm stem on my XC bike and a 5cm stem on my trail bike. I'm about your size, judging by those measurements.

I think I would start with a cheap 6-7 cm stem and go from there. Truvativ AKA is a good cheap stem.

[ColonelJLloyd]

Doesn't "reach" mean distance from center of (horizontal) bar to the front end of the drops? Unless you are holding the bar at the end (which shouldn't be the case on a rando bar), your "reach" is going to be much shorter.

I think you're over-thinking it. :) Go with an 80mm stem and see how it works. I think that's a good middle ground, and where I typically start. I believe I have 80mm and 90mm stems you can borrow, if you want to test it out. Shouldn't be much more than $5 for postage.

I've been accused of over-thinking for sure.

I think you're correct about the bar reach distance, yes. But, that would be about where the hoods are, so should be pretty relevant. But, yes, my hands are on the flats more than most other spots.

I have a 6cm stem on my XC bike and a 5cm stem on my trail bike. I'm about your size, judging by those measurements.

I think I would start with a cheap 6-7 cm stem and go from there. Truvativ AKA is a good cheap stem.

Thanks, Christian. Yes, 6' with an 80cm saddle height.

A really wide bar like this is new ground for me. Any recommendations on grips and shifter/brake lever placement?

[gdw]

How do you intend to use the bike? Do you want to set it up to ride technical single track or smoother trails and fire roads? Shorter stems, under 90mm, are great for challenging terrain but you might find a medium length stem, 90-110, is more comfortable for all-around use especially if you're new to mountain biking. Checking out the specs on similar sized production bikes can be pretty helpful.

[ColonelJLloyd]

Ah, thanks. I'm a noob so I guess I'm going for a pretty generic trail setup.

[gdw]

Call Lynsky's customer service and see what they recommend. Their build kits give you a choice of medium length stems, 90-110mm, so they might feel their frames are optimized for those lengths.

[p nut]

Bar/stem length is personal preference. I had an AM bike set up with a shorter 70mm stem and 800mm bars. That was a bit too extreme for me, since I do zero hucking (on purpose, anyway). And trees seemed to get in my way more often than I wanted. Found my sweet spot was ~720mm bars and 90-100mm stem (depending on ETT). I primarily ride XC with lots of techy climbs and downs. Note, my main ride is a Singlespeed, which necessitates a wider bar. On my secondary geared bike, my bars are 660mm, which I'm quite happy with.

PS - My favorite bar to date is a Seven Ti custom. $150 gets you the length and sweep you want.

[d_douglas]

I've been accused of over-thinking for sure.

I think you're correct about the bar reach distance, yes. But, that would be about where the hoods are, so should be pretty relevant. But, yes, my hands are on the flats more than most other spots.



Thanks, Christian. Yes, 6' with an 80cm saddle height.

A really wide bar like this is new ground for me. Any recommendations on grips and shifter/brake lever placement?

I have the same saddle height and am one inch taller. I ride a large Chromag 29er and went against chromags recommendation of 60mm to get an 85mm. I have just spent a week of vacation riding on pretty hard trails (as well as swimming with my kids and pounding daily ice creams!) and I would say the fit guess was pretty dead on. I would say that 70mm is a good starting point and my guess is that you will be 10mm on either side of that.

Truvativ does make a good cheap stem.

[gomango]

AKA is a good cheap stem.

I put one on my Yeti SB5c.

Works fine and I don't really care as it's covered by a mountain bag and GPS.

[John H.]

Thing is, mtb fit is not as precise as road fit.
Lots more variables, and bar width affects reach a bunch.
Start with a saddle position that is similar to road position.
Shoot for a reach that is longer than road top- shorter than reach to hoods.
Bar drop should be less than road bike- heck, an mtb can have zero drop and still handle well. But if you want a starting point, shoot for half the amount of drop that your road bike has and work from there.

Don't be afraid to cut those bars down if they feel too wide.

[christian]

John speaks the truth. My saddle height and setback match the road. Other than that, it's a whole different world.

[HenryA]

John speaks the truth. My saddle height and setback match the road. Other than that, it's a whole different world.

Ill second this. John seems to have a good grip on MTB fit.

[ColonelJLloyd]

Super appreciative of the guidance, all. Saddle position will match all my bikes. No fear in cutting the bar.