I am fixing up a 90s non-suspension mtb for my son and me. We are both exactly the same size; inseam, arms, etc. We've done all the measurements. At 15! Anyway, I ride a surly disc trucker, 58cm. The top tube is 586mm. It's OK for me. I could go a bit shorter. I'm thinking a 100mm stem might adjust things just fine. I would shoot for a TT of around 580mm for my next bike. That's my reference.

So last summer I find a Univega MTB from the 90s. Frame made in Taiwan. I can't remember what size it's supposed to be, but I measure the TT to be right around 596mm. I don't have any experience with mountain bikes. I've done some research and I think that mtbs have longer top tubes because they use straight handlebars. Is that correct? What I'm wondering is if buying a trekking bar will make up for the long top tube since we want to use this bike as an around town, grocery getter rather than a mtb. We are both 6 feet tall with inseams around 33.5" to 34.0".

Just looking for opinions. Is the bike just too big, or will it be OK for someone who rode 58cm to 60cm bikes back in the day with trekking bars and shorter stem (100mm - 110mm).

Thanks for any help.

I have a similar problem -- and almost same dimensions at 6'1" and 33" inseam. My particular solutions may or may not work for you also, but I'm also pretty happy with a 59 cm TT and 100 mm stem (or even shorter perhaps).

Currently fixing up a 20" Cannondale. Leg length is good but top tube is 23.25 inches, or 59 cm, and feels very long. To fix this, I decided to go with a Nashbar Comfort ATB stem for $12 and 100 mm, and Nitto Albatross bar to bring the reach up 1-2" and hand grips back (and parallel) almost 3-4". Haven't quite completed it yet, so I don't know how the upright position will work with thigh strike, but it looks pretty good so far.

Also thinking about fixing up a 19.5" Trek. It's half an inch shorter but the top tube is still 59 cm! Thinking about going with a short 80 mm Nitto Dirt Drop to bring up the handlebars another couple of inches -- they're supposed to have almost 4" of travel, plus the 71 degree head angle should be bringing the bars up and back even more -- and a pair of short flared drop bars.

Not quite done configuring either one yet, but I'll post when I do. I hope that helps.

If you're riding a 58 cm road bike, a MTB in the 19-20" range would be about right. Don't worry about the MTB's longer top tube. That's because you'll generally be using a shorter stem and flat MTB bars don't have any forward reach to the lever hoods. Think about it--on a road bike, with your hands on the hoods, they are 7-9 cm ahead of the stem.

You'll probably still be sitting more upright on the MTB than your road bike anyway. And if you find that you've got too much weight on your wrists, don't hesitate to slide the saddle back, and lower it a bit, before feeling compelled to purchase taller riser stems.