Stem and fit for 'cross...

[livingminimal]

I realize cross season is over, but I am already thinking about next year. I am moving off my Steel Stinner cross bike (590 ETT) and likely going back to carbon.

I really love the new Focus frames, but the longest ETT is 577. :eek:

I ran a 110 0 degree thomson....

I mean, is the logical solution just going up to a 120 and being 3mm shorter? I can make that up by going from a 16mm (thomson curve) setback to a 25mm and going forward a bit...

I am not always the best in terms of factoring everything together to figure out fit...

For reference, my Pegoretti is a 58cm TT and I ride it with a 130 stem and 25mm setback on the road...My focus is a tad bit longer, 583, and I will probably run a 120 on it.

Should I be looking for a longer ETT cx rig? The usual suspects, Felt, Focus, Ridley, etc all make such short ETTs and recommend them for guys my height...6'3"

Just looking for general feedback etc before I find time to get in-depth with my fitter, which around this time of year is tough.

Thanks-

EDIT: Playing with BikeGeo.Net turns over this comparison...column 1 is my current cross bike, column 2 would be a 2016 Mares...

Can anyone interpret how the "feel" would be different as a result?

Wheelbase(13) 1035 1044 0
Reach(frame)(14) 392 400 0
Stack(frame)(15) 610 580 0
Reach(spacers)(16) 389 390 0
Stack(spacers)(17) 620 608 0
Reach(stem)(18) 493 494 0
Stack(stem)(19) 654 644 0

[Lovetoclimb]

My general experience with the 4 cross frames I have used have seen all but one with a 1cm shorter TT and 1-2cm taller HT stack than my road bikes.

For a while I was running the same length and angle stems, but I recently switched from 120 +/- 6 degree stems to 110 or 100 0 degree Thomsons bringing my handlebars up even further. I like this more and it has helped me transition my cross setup away from the traditional roadie long and low stance I was used to. Coincidentally I feel more confident railing into loose or off camber stuff as well ....

[tuscanyswe]

I realize cross season is over, but I am already thinking about next year. I am moving off my Steel Stinner cross bike (590 ETT) and likely going back to carbon.

I really love the new Focus frames, but the longest ETT is 577. :eek:

I ran a 110 0 degree thomson....

I mean, is the logical solution just going up to a 120 and being 3mm shorter? I can make that up by going from a 16mm (thomson curve) setback to a 25mm and going forward a bit...

I am not always the best in terms of factoring everything together to figure out fit...

For reference, my Pegoretti is a 58cm TT and I ride it with a 130 stem and 25mm setback on the road...My focus is a tad bit longer, 583, and I will probably run a 120 on it.

Should I be looking for a longer ETT cx rig? The usual suspects, Felt, Focus, Ridley, etc all make such short ETTs and recommend them for guys my height...6'3"

Just looking for general feedback etc before I find time to get in-depth with my fitter, which around this time of year is tough.

Thanks-

EDIT: Playing with BikeGeo.Net turns over this comparison...column 1 is my current cross bike, column 2 would be a 2016 Mares...

Can anyone interpret how the "feel" would be different as a result?

Wheelbase(13) 1035 1044 0
Reach(frame)(14) 392 400 0
Stack(frame)(15) 610 580 0
Reach(spacers)(16) 389 390 0
Stack(spacers)(17) 620 608 0
Reach(stem)(18) 493 494 0
Stack(stem)(19) 654 644 0

You don't want a longer tt on the mares since the data you provide here suggest that the mares allrdy has a longer reach than your custom cross?!

Without access to the data you provided for these numbers i would assume that the seat tube angle on the focus is steeper than on your custom. So you would need more setback if you wanted the same fit, hence the longer reach on the bike despite the shorter ett.

If anything it seems you would want a shorter stem if the goal was to duplicate the contact points?

I dare not speak of what such small changes would feel like regardless. I imagine it would be a guessing game how you would feel on one bike or the other more than anything else.

[livingminimal]

You don't want a longer tt on the mares since the data you provide here suggest that the mares allrdy has a longer reach than your custom cross?!

Without access to the data you provided for these numbers i would assume that the seat tube angle on the focus is steeper than on your custom. So you would need more setback if you wanted the same fit, hence the longer reach on the bike despite the shorter ett.

If anything it seems you would want a shorter stem if the goal was to duplicate the contact points?

I dare not speak of what such small changes would feel like regardless. I imagine it would be a guessing game how you would feel on one bike or the other more than anything else.


well I think I can get similar/comparable/same contact points for sure, it seems like even more so if I play with the spacers some...
For angle reference:
Stinner Mares
Head tube angle(7) 72 71
Seat tube angle(8) 72 73

Comment about setback make sense; running the weird bent 16mm setback Thomson and would be swapping out most likely for a 25mm 3T setback.

[bewheels]

Perhaps I missed it, but the focus (no pun intended) on your original posting is on the reach/drop. That comes after getting the hip/knee/pedal established which is the relationship between the seat placement and the bottom bracket set by the seat tube angle and seat post setback. The Seat post angle being the true fixed element that you will need to work around. A 1 degree difference on a frame this size makes a big difference. I am around 6'3" and have trouble with 73 degree seat tube angles.

[livingminimal]

Perhaps I missed it, but the focus (no pun intended) on your original posting is on the reach/drop. That comes after getting the hip/knee/pedal established which is the relationship between the seat placement and the bottom bracket set by the seat tube angle and seat post setback. The Seat post angle being the true fixed element that you will need to work around. A 1 degree difference on a frame this size makes a big difference. I am around 6'3" and have trouble with 73 degree seat tube angles.

Just curious, because I am trying to understand it all, how does a 73 st angle give you difficulty?

[tuscanyswe]

At some point finding a seatpost with enough setback will be challenging if you are one of those who need a lot of it on a 73degree sta.

[livingminimal]

At a 72 sta before I was using a 16mm setback post and it was fine. Had a 25 ready to go for the 73 degree. Will it suffice?

[tuscanyswe]

At a 72 sta before I was using a 16mm setback post and it was fine. Had a 25 ready to go for the 73 degree. Will it suffice?

Play around in bike cad perhaps. It also matters at what height you sit at with the different angles.
im 6 2 and I'm not even close to having issues with 73degree sta.

[bewheels]

Just curious, because I am trying to understand it all, how does a 73 st angle give you difficulty?

Let me first state that while I have experience in these matters that span a couple of decades, there are others on this forum that certain know more and/or can explain it better. Also, I fall into the camp in which I believe (and what has worked for me) that the hip/knee/foot relationship is the same on all my bikes - mtb, cross, and road. Although reach and drop is different on those set-ups. I am excluding triathlon and time trail set-ups from this.

If you were to put the same seat tube angle on a 50cm and a 65cm frame, the position of the seat does not go behind the bottom bracket at a rate that matches the proportional changes in the people that these frames would fit. If you are using some type of software I assume you could run these scenarios to see what happens.

As was mentioned by others, it is hard for me to find a seat post with enough setback if I use a 73 degree angle frame. 72 degrees work much better for me. While my femurs might be a little long, I am pretty normal in proportion.

But as was also mentioned by others, some people fit 73 degree angle frames just fine.

Regardless of what works for me, my point is that getting that relationship needs to be taken into account before, or with, sorting out the reach.

As a historical data point, back in the day there were more sizing options and those options included more changes to items then just top tubes and head tubes. Of course offering a lot of stock options is very difficult from both a manufacturing and retail perspective.