Heres the gig...I currently ride a 61cm tt but have ridden comfortably down to 59cm tt. I have the opportunity to purchase an XL TCR composite ride with a 61cm tt or a Moots compact 61.5cm with 6/4 pipes and a 59.5cm tt. Do you think that 1.5cm diff in tt lengths really is a big deal with the adjustments made with saddle fore/aft and stem adjustment. The geo is fairly similar except for the 1.5cm tt diff and shorter chainstays on the TCR. I'm thinking that I can modify my fit and get the same measurements that I ride now... What do you think??? Whats the difference in sizing for frames you ride???

Any experience with the snap of these frames is also appreciated....

Any and all (in)sane comments welcome...

J

It's difficult to comment since you left out the stem length and seat tube angle that goes with the 61cm TT. Both are relevant when calculating reach differences.

The MOOTS has a 72.5 degree STA compared to the TCR's 73. This makes the effective TT length of the MOOTS about 7mm shorter, or 58.8cm, compared to the TCR.

If you can get both at the same price, no question get the MOOTS. Just look at those welds.

Other than that, the MOOTS has a 6deg sloping top tube whereas the Giant has 10 deg (?), not absolutely sure and too lazy to check.

It shouldn't make much of a difference once you get the same overall reach for both bikes. 1 will feel very very slightly twitchier.... but you probably won't notice it. What you will notice is the difference in feel of both materials.

Im running a 120 stem on my current ride so I was thinking that I could run a setback post and a 130 stem or just try the 120 with the post alone. The head angle on the moots is 74.25 compared to 73.5 on the moots which I would think effectively lengthen the tt. Maybe my logic is backwards....

What's the seat tube angle and wheelbase of the Moots, the Giant and your current bike?

Edit: Ok, just checked the Moots site and they don't list wheelbase. I dunno... STA is 72.5 vs. 73 on the Giant so as C-40 mentioned the Moots is effectively even shorter... I don't know how anyone can mess with their setback but that's me...setback is the thing I adjust first on any bike and it's always the same. And I'd definitely want to know how short that wheelbase is vs. my current ride. You can often get a smaller bike to "fit" by going with a longer stem, but chances are with the shorter wheelbase it will feel less stable at higher speeds.

custom Independent Planet X with a 72.5 ht angle and 72 st angle. 61 tt and 6.7 drop. I wanted a comfortable do-all machine but want something with more snap on the jump. The seat tube is 64 c-c and I do feel that I'd be comfortable as well on something a little smaller. I guess that I dont understand how a more slack st angle shortens the tt length. Please enlighten...

J

You DON'T mess with your saddle fore-aft position to control reach to the bars! Full stop. You set your saddle relative to the BB, and then adjust reach with stem length. Double check that each of these top tubes is measured the same. If Giant measures along the tube, that would make their TT seem longer.

The difference in HTA won't make any significant difference in the reach.

The reason a slack STA makes the TT shorter, COMPARED to a steeper one, is that the saddle must be moved forward to place it in the same position relative to the BB. The comparison is being made with the rider in the same position relative to the BB. That's why I asked about the STA of your current bike.

If you've got a 73 degree STA on your current bike, then there's a 2cm difference to make up. A 130 stem will take care of 1cm. Depending on the brand of handlebar you're using it may not be difficult to get 1cm from a change of handlebars. If not, the extra 1cm could come from moving the saddle back 1cm. Once again, it depends on where you're at now. A lot of folks religeously place the knee over the pedal spindle and wouldn't try anything else. I find that anywhere from directly over the pedal spindle to 2cm back is useable. I currently use about 2cm back for enhanced climbing torque and I've suffered no ill effects from the change. A large rider might be able to tolerate a bit more setback. Other folks will claim that a few milimeters of saddle movement will make their knees hurt. I don't believe that's often true because it's difficult to take a measurement with that much accuracy. Still others claim that you can place the saddle AHYWHERE you want, relative to the BB and it makes no difference in performance. I don't subscribe to that theory either. I find a definite improvement in the ability to apply torque as the saddle is moved back. I can live with the knee 1cm behind the pedal spindle or 2cm behind, but I'd rather climb mountains with the knee back 2cm. If I was riding moderately rolling terrain, a further forward position would work fine.

I've never seen a geometry chart with only one TT length that wasn't a horizontal length.

Although I agree that it's not wise to adjust the saddle to change the reach to the bars, some folks have never experimented with saddle placement enough to really know what works best. Many don't have a clue where their knee is placed relative to the pedal spindle. Some folks use measurements like how far the saddle tip is behind the BB and don't even consider the differences in saddle length and width between different models.

Personally, I find that there's at least a 1cm range that doesn't make a significant difference in performance and doesn't bother my knees. If I was to err, I'd err on the side of further back.

custom Independent Planet X with a 72.5 ht angle and 72 st angle. 61 tt and 6.7 drop. I wanted a comfortable do-all machine but want something with more snap on the jump. The seat tube is 64 c-c and I do feel that I'd be comfortable as well on something a little smaller. I guess that I dont understand how a more slack st angle shortens the tt length. Please enlighten...

J

Ok, you'll get roughly the same fit as your cross bike with a 13 cm stem on the Moots and an 11cm stem on the Giant, if that helps. Both the Giant and the Moots will have a shorter wheelbase than the cross bike.

Thanks for all the replies! It will certainly help in my decision. I just want to be sure of my measurements before I drop the coin. Ive had my machine for close to 3 yrs now and the fit is really dialed in. I did change saddles recently to an Arione and now is positioned where my knee is in line with the pedal spindle, although I prefer or it feels better to be further back over the rear wheel where my knee is behind the spindle. After reading and re-reading your informative responses, I feel like I will be able to fit comfortably on the moots. Even though it has a 1.5cm shorter tt length than I'm on now, I will be able to get a more comfortable postion behind the pedals and fit accordingly. thanks again for all you insight.

J

The difference in HTA won't make any significant difference in the reach.

The reason a slack STA makes the TT shorter, COMPARED to a steeper one, is that the saddle must be moved forward to place it in the same position relative to the BB. The comparison is being made with the rider in the same position relative to the BB. That's why I asked about the STA of your current bike.

If you've got a 73 degree STA on your current bike, then there's a 2cm difference to make up. A 130 stem will take care of 1cm. Depending on the brand of handlebar you're using it may not be difficult to get 1cm from a change of handlebars. If not, the extra 1cm could come from moving the saddle back 1cm. Once again, it depends on where you're at now. A lot of folks religeously place the knee over the pedal spindle and wouldn't try anything else. I find that anywhere from directly over the pedal spindle to 2cm back is useable. I currently use about 2cm back for enhanced climbing torque and I've suffered no ill effects from the change. A large rider might be able to tolerate a bit more setback. Other folks will claim that a few milimeters of saddle movement will make their knees hurt. I don't believe that's often true because it's difficult to take a measurement with that much accuracy. Still others claim that you can place the saddle AHYWHERE you want, relative to the BB and it makes no difference in performance. I don't subscribe to that theory either. I find a definite improvement in the ability to apply torque as the saddle is moved back. I can live with the knee 1cm behind the pedal spindle or 2cm behind, but I'd rather climb mountains with the knee back 2cm. If I was riding moderately rolling terrain, a further forward position would work fine.

Good comments! My experience is similar; you have much more flexibility with your fore and aft position than is generally advised in the popular literature. One area that you should think about is how your fore and aft postions affects the balance and handling of the bike. Moving your COG fore and aft 1-2 cm can have a dramatic impact on the way the bike corners and descends.

A good point, but I really haven't noticed a significant difference in cornering ability and I ride very demanding mountain descents on nearly every ride. I only tap the brakes before a few of the tighter right-hand hairpins. Most corners I take at 35+.

Moving the saddle by 1cm should change the weight balance by 2%. The 2cm move I made probably took 5 lbs off the front wheel and moved it to the back.