Probably a dead horse: changing to a shorter stem to make up for a longer top tube

[B4_Ford]

I recently picked up a Land Shark that has a longer top tube than my other bikes. I typically ride a 57-58cm top tube with a 120mm stem. This particular frame has a 60cm top tube. Otherwise the dimensions are pretty close to my other frames. Will dropping down to a 90mm stem on the Land Shark significantly compromise handling? I’m not going to be racing and I don’t often exceed 30mph on descents. I’m at the older and slower point of disgracefully aging. I definitely want to make reasonable adjustments in hopes of making it a keeper that I ride comfortably as opposed to just wall art.

[lavi]

Thanks for posting. I think about these things to on different bikes.


I guess if setback is the same between bikes....that's the most important thing. However, I also would wonder if a shorter stem would affect handling.

But then I think that sometimes, when looking to compensate for a shorter stem, I end up (on purpose) putting my torso more forward (moving forward on seat) to accommodate.

Inquiring minds want to know.

[B4_Ford]

Originally Posted by lavi

Thanks for posting. I think about these things to on different bikes.


I guess if setback is the same between bikes....that's the most important thing. However, I also would wonder if a shorter stem would affect handling.

But then I think that sometimes, when looking to compensate for a shorter stem, I end up (on purpose) putting my torso more forward (moving forward on seat) to accommodate.

Inquiring minds want to know.

I was also toying with the idea of trying out a zero setback seat post.

[lavi]

Originally Posted by B4_Ford

I was also toying with the idea of trying out a zero setback seat post.

Zactly the stuff I think about. That's when I start worrying about setback.

Sometimes I just need to lay off and trust what my body tells me. I've been riding long enough that I know when a fit is off and won't work. Setback, non-setback, this stem, that stem...if it feels good, do it (for up to 3 hours, then the fit better be good).

[robt57]

Originally Posted by B4_Ford

I was also toying with the idea of trying out a zero setback seat post.

Trying? To me if the ST is shallow as to require a post with zero offset to achieve your correct position behind the BB.. Try?

Also, is the TT longer as a result of said STA, and for that matter possibly due to a steep HTA, pertinent issues...

[mhespenheide]

Get your setback dialed first, then check the distance from the saddle to the bars.

The best way that I've found to do this uses a trainer and a meter stick. Mount the bike that you want to use as your baseline/standard into the trainer. Push it back against a wall so that the rear tire is touching the wall. Measure from the wall to the center of the bottom bracket. Measure from the wall to the front tip of the saddle. Subtract (wall to BB) - (wall to saddle tip). Call this "setback".

Change bikes in the trainer. Get the bike back into position. Measure from the wall to the bottom bracket, then subtract the setback. Move the saddle forward or backward as needed to get the same setback. This is an iterative process in the sense that as you move the saddle forward and back, you'll likely need to tweak the saddle height a touch, which means that you'll need to tweak the fore/aft as well.

Now: this isn't a prefect method. Some bikes require weight a little farther forward to handle properly; others need a little rear-bias. And it presupposes that you're using the same saddle and length of cranks. But it's a good starting point.


After you get the setback dialed, then start looking at the stem length.

[mhespenheide]

Originally Posted by robt57

Trying? To me if the ST is shallow as to require a post with zero offset to achieve your correct position behind the BB.. Try?

Also, is the TT longer as a result of said STA, and for that matter possibly due to a steep HTA, pertinent issues...

I've never followed the idea that HTA changes the TT length; to me, I visualize the HTA pivoting around the connection point between the top tube and steerer tube.

On the other hand, STA absolutely affects reach, or what Grant Peterson called "Z" decades ago. I have bikes with 72.5 and 74 degree STA's that come out nearly identical in Z after the saddle is in the same position.

[joeminglin]

Originally Posted by B4_Ford

I recently picked up a Land Shark that has a longer top tube than my other bikes. I typically ride a 57-58cm top tube with a 120mm stem. This particular frame has a 60cm top tube. Otherwise the dimensions are pretty close to my other frames. Will dropping down to a 90mm stem on the Land Shark significantly compromise handling? I’m not going to be racing and I don’t often exceed 30mph on descents. I’m at the older and slower point of disgracefully aging. I definitely want to make reasonable adjustments in hopes of making it a keeper that I ride comfortably as opposed to just wall art.

Shorter stem shouldn't compromise handling. Also take into account handlebar reach. You can get a 10mm shorter reach bar and use a 100m stem. The contact points should be the same (at the hoods). There is also no harm in moving your saddle forward.

[Dead Man]

short stem might not ~actually~ affect handling, tho in my perception it does make a bike feel weird in the turns... but for me, even if thats all in my head, short stems just look awful..

all that i have to offer, but i give it all to you freely.

[NHAero]

My Bob Jackson was made for me in 1972, and it's way too big. Ideas of fit have changed. So to keep riding it I have a 60mm stem. It rides and handles fine, with the added benefit that a handlebar bag load affects handling less than it does on a bike with a more normal stem length.

Originally Posted by B4_Ford

I recently picked up a Land Shark that has a longer top tube than my other bikes. I typically ride a 57-58cm top tube with a 120mm stem. This particular frame has a 60cm top tube. Otherwise the dimensions are pretty close to my other frames. Will dropping down to a 90mm stem on the Land Shark significantly compromise handling? I’m not going to be racing and I don’t often exceed 30mph on descents. I’m at the older and slower point of disgracefully aging. I definitely want to make reasonable adjustments in hopes of making it a keeper that I ride comfortably as opposed to just wall art.

[bil]

I have one bike that I ride with a 80mm stem, no problem at all.
yes, not ideal but zero issues and still perfectly comfortable.