Alison Chaines

Bought a used bike a few days ago. Seller told me it was a Medium but after getting it delivered and setting it up I noticed that the frame is somewhat smaller than my previous bike. For instance, the horizontal top tube measurement is 15 mm shorter with 580 mm vs 595 mm. According the manufacturers data this frame is a Small. Theoretically, can I successfully replace the 90 mm stem to a 120 mm to compensate for the smaller frame size? My previous bike felt perfect, like I was riding "in" the bike. But this bike feels more like I'm riding "on" it. Can the stem make the difference I'm looking for? I'm not planning any technical riding, but rather faster XC highway style trails/roads. I'm sorry for asking before I've exhausted other options - but I'd like to know what to expect before hand based on other peoples experiences.

What do you think is a good size frame for someone who's 1730 mm with above average long arms and legs?

Pamestique 

I totally don't get any of your measurements...but its not unusual for "medium" bikes to be sized differently depending on fork angle, top tube length etc. Just a longer/shorter stem can make a big different. The Juliana I just purchased (which is a medium) has a much shorter top tube than my old Superlight (also a medium) so I changed out the stem length and handlebars (too wide) and it makes a real difference. With your body measurements you might have done better with a woman specific bike (like i purchased) but most bikes can be adjusted with a little work to your requirements.

BTW if it means anything for you I am 5'8" with average arms and longer legs and am comfrotable on a medium.

ColinL

if the TT is 15 mm shorter, why are you figuring on a 30mm longer stem? I would start with 10-20mm longer depending on your fit on the original bike and how tall the head tubes are on each bike.

lubes17319

Or keep the same stem, and put on wider bars.

Alison Chaines

This is my previous bike, 19" one with 90 mm stem:


This is the one I bought a few days ago, it's the small frame marked with red dots:


I found a 110 mm stem in one of my cycling stuff boxes. I'm going to try it. Thing is, I sold my previous bike 6 months ago and have sort of forgotten how it felt exactly. I only remember that it felt really nice, low and fast.

Both bikes have pretty narrow grip and a 90 mm stem. Can the 110 mm stem compensate the 15 mm difference in horisontal top tube measurement?

I can definitely live with the firmer steering of a longer stem since I'm planning to ride this on dirt roads mainly. My main objective is getting my saddle position in the optimal position over the bottom braket and a bit more weight distribution of the front end.

I'm in Sweden by the way. Both these are German bikes. Ghost and Focus...

Siu Blue Wind

19 inch frame? How tall are you?

I'm 5'5", with a 32 inch inseam. my Konas are 15 for the FS and 16 inches for the hardtail.

ColinL

your body will remember the fit. you just need to experiment with stem length and angle, and probably saddle fore/aft placement, changing only one thing at a time and riding at least 2 hrs on each adjustment. (unless it feels way wrong right away-- then of course you change it immediately.)

and yes, it is completely normal to change stem length depending on the bike's top tube length in order to match the reach you prefer.

JiveTurkey

Before messing with the stem (reach, generally) make sure your saddle is in the correct fore/aft position, relative to the bottom bracket--along with correct height, of course.

Your new bike's seat tube angle is just a tad steeper (by 0.5 degrees), which means your saddle will need to be slid back a little on the seatpost, to put it in the same place relative to the BB, effectively increasing the top tube length, again, by just a tad.

You may only need an extra 10 mm on the stem. But, of course, go with what feels good.

Along with reach, don't forget to adjust the height of your bars (relative to the saddle). The stem's length, angle, and how high up it is on the steerer all affect reach and height.

With various stems, you should be able to adjust the bike to something close to what you had before and hopefully to something comfortable.

I've gone through many-a stems to find the perfect fit.

Good luck.

Alison Chaines

I am 5'8" or 173 cm with 33" inseam and long arms. Primarily as I am a road bike rider, I prefer the racier positions and trails. I prefer to sit "in" the bike than "on" it. The 595 TT measument plus 90 mm stem on the Ghost Lector felt perfect. So that was what I was going for with the new bike. As far as the other measurements, the frames would've been identical aside from the head tube angle, which is steeper on the Focus.

I will experiment for sure and maybe I'll find a new "perfect".

kenhill3

Setback seatpost would be an option.

Tulok

it takes 5 minutes to swap the stem, try it and let us know!

specbill

I don't want to bring you down but based on the two bikes detailed above, if the 19" fitted you perfectly and gave you a 'down in the bike feel', I don't see how the 17.5 will get you to the same place with just a change of stem length. A longer stem should help some for sure but I just can't see how the 17.5 will ever feel the same with such different wheelbases ...angles. hopefully I'm wrong. Regardless, you should still be able to get it to where while it may feel different, it will still get the job done for you. Good luck.

Bill J.

roccobike

I can understand why the seller said it was a "medium". 440 mm seat tube = 17 inches which is a medium size with many brands including Specialized. I think you should try working with the frame, possibly using the set back seat post or at least pushing the saddle all the way back along with the longer stem. After trying a small frame (16 inches) I decided to trade both hardtail and dually for small size frames.