Bike Geometry

[biker72]

For years I've ridden 60cm Treks....some mid level road....some entry level road. My last Trek was a 60cm 2100 Aluminum frame carbon fork and seat stays. Factory standard geometry.

My newest acquisition is a Custom TI Serotta. I'm a little puzzled with the geometry.
http://graphicfxs.com/SerottaTI.jpg

The Serotta has a 58cm C-C seat tube.
55cm C-C top tube and wheelbase of about 100cm.
Serial# CTI 582578
Full Campy Record 9 speed.

This is without a doubt the best riding bike I've ever had.

With this non-standard geometry should this bike be more or less likely to be unstable at higher speeds? Or have any other problems??

[tuscanyswe]

I cant really awnser you questions but id be very suprised if the frame had any kind of "problems"

Im a geometry novice but what strike me is that the toptube on the custom serotta you have now is only 55cm. You also seem to have a relative short stem. Your saddle is also pushed very far forward in the clamp. Im thinking your current setup must be very different from your standard 60cm trek?

Im having trouble picturing how you set up your trek to have similar contact points considering how short you have setup your serotta. Maybe this is contributing to your great experience? Not to take away anything from a serotta frame cause im certain the frame do have a great ride!

[goonster]

Do you still have one of the 60cm Treks you rode previously? Can you post a picture of one, set up the way you ride them?

It's almost impossible to make predictions or draw conclusions about "stability" based on the specs you have posted here. Saddle all the way forward is something I also don't like to see, generally, but that's my problem . . .

[biker72]

I cant really awnser you questions but id be very suprised if the frame had any kind of "problems"

Im a geometry novice but what strike me is that the toptube on the custom serotta you have now is only 55cm. You also seem to have a relative short stem. Your saddle is also pushed very far forward in the clamp. Im thinking your current setup must be very different from your standard 60cm trek?

Im having trouble picturing how you set up your trek to have similar contact points considering how short you have setup your serotta. Maybe this is contributing to your great experience? Not to take away anything from a serotta frame cause im certain the frame do have a great ride!

Sorry, this is not a current photo of the bike. The saddle is actually set back to the mid point of the rails.

[biker72]

Do you still have one of the 60cm Treks you rode previously? Can you post a picture of one, set up the way you ride them?

The Trek is for sale at my LBS. I'll try and get a photo later today or tomorrow for sure.
And maybe get a better photo of the Serotta.... :o

[veloduffer]

For years I've ridden 60cm Treks....some mid level road....some entry level road. My last Trek was a 60cm 2100 Aluminum frame carbon fork and seat stays. Factory standard geometry.

My newest acquisition is a Custom TI Serotta. I'm a little puzzled with the geometry.
http://graphicfxs.com/SerottaTI.jpg

The Serotta has a 58cm C-C seat tube.
55cm C-C top tube and wheelbase of about 100cm.
Serial# CTI 582578
Full Campy Record 9 speed.

This is without a doubt the best riding bike I've ever had.

With this non-standard geometry should this bike be more or less likely to be unstable at higher speeds? Or have any other problems??

I think you should look at the trail, head tube and seat tube angles, bottom bracket drop and difference between front-center and chainstay lengths.

[biker72]

Current Serotta photo has been posted.

[Mike748]

Best riding or best fitting?

I have a 59x55 Ottrott which fits me well and rides/handles/performs beautifully. As long as the bike was designed well, the short top tube shouldn't impact the ride. Except maybe front center and toe overlap.

I agree with the others that you made a big change going from a 60cm TT to a 55... but you can accomodate some of that with a stem change. You need a sexier stem anyway :rolleyes:

[NRRider]

You lucked out if this fits well. I find it's tough to get used custom frames with this geometry. Would fit me perfectly.
I think the 100cm wheelbase is great for a bike with a 55cm top tube. Looks like they got there with a slacker (but not too slack) head tube angle.
Leave it to others to answer your question, but I'd be surprised if it didn't handle well.
Very sharp looking ride!

[biker72]

Best riding or best fitting?

I have a 59x55 Ottrott which fits me well and rides/handles/performs beautifully. As long as the bike was designed well, the short top tube shouldn't impact the ride. Except maybe front center and toe overlap.

I agree with the others that you made a big change going from a 60cm TT to a 55... but you can accomodate some of that with a stem change. You need a sexier stem anyway :rolleyes:

Mike, this bike fits like it was custom made for me. It does put me in a more upright position but feels great like it is.

[1happygirl]

I see how it would be a great bike. It's awesome looking. I'm jealous. Pruitt, et. al are proponents of the less stretched out movement. Did I say it's awesome and I'd like to have it. yeah. enjoy

[biker72]

You lucked out if this fits well. I find it's tough to get used custom frames with this geometry. Would fit me perfectly.
I think the 100cm wheelbase is great for a bike with a 55cm top tube. Looks like they got there with a slacker (but not too slack) head tube angle.
Leave it to others to answer your question, but I'd be surprised if it didn't handle well.
Very sharp looking ride!

Thanks NRRider.
This was an eBay purchase and was described as having a somewhat shorter top tube. The dimensions the seller gave were not totally correct. Just for the heck of it I did some measurements a couple of weeks after I started riding the bike. I couldn't believe the numbers.

The only thing I've changed is the crank arms from 170mm to 175mm.

[bobswire]

Another gorgeous Serotta frame.

[biker72]

Thanks to everyone for the kind comments about my bike. :)

I need to get that SHIMANO name off those pedals.. :D