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Discussion Starter · #1 ·
Since I'm pretty much a noob to cross, I'll ask about frame sizing. I currently ride a 57 c-c road bike (Look kg461) and my frankencross bike is an old Gitane Road/tourer, size unknown, prolly 58 c-t. I can get a VanDessel G&T for a good price, but it's a 58 c-t w a 57c-c TT. I'm just shy of 6' and have about a 32.5 inch inseam. I'm thinking that even though the VD is a good buy, it may be too big. Any thoughts?? I don't want to spend $500 on a bike that's too big.(frame/fork)
 

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Discussion Starter · #3 ·
That's what I'm thinking. Bummer, though.
 

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well if it is a 58 c-t

that means it's 57 c-c most likely. that may be enough. I have a 34 and change inseam and ride 59's c-c with 59ish TT's.
 

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Too big. If you plan to race the thing, you need to go one size smaller than you normally would ride. My Salsa is a 54 with a 55 top tube. My Damocles (road) has a 56.5 top. Both bikes have the same cockpit setup. I can tell the Salsa is smaller when I get on it, but the feeling goes away after about 10 minutes.

I'm 6'1" with a 33 inseam.

You should probably look for something with a 55 or so top. Cross bike sizing is even stranger than road sizing, so always look for TT length over the size of the frame.
 

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both of you should ride

Ridley Cross bikes as you both sound long legged, short torsoed. 57 TT would stretch you too far. your leg lengths would put you both over a 57 ST but your reach is 55-56.
Italian Geometry. 54 ST for a 33 inch inseam? that's some standover.
 

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Discussion Starter · #7 ·
Tell me about it. I have a 90cm stem on my road bike. Ridley, eh? Saw one on e-bay....
 

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Ridley cross bikes size up BIG. The bikes are very tall. I needed a 54 Ridley as well. The Salsa fits me perfectly. Watch a Euro cross race. They are all riding smaller frames. Mounts and dismounts are much easier on a smaller frame.

This is my fourth cross bike and all of them have been 54 or 55cm.


One of the old JTS race bikes...(54cm)

 

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I'd go by toptube length.

I'm about 5'8" with a 32" inseam. I am riding a Gin and Trombones size 54. I used to ride a Redline size 52. They fit the same because the top tubes are about the same. By the way, I really like the G&T. The only disadvantage is the brake pad clearance on the fork.


Kram59 said:
Since I'm pretty much a noob to cross, I'll ask about frame sizing. I currently ride a 57 c-c road bike (Look kg461) and my frankencross bike is an old Gitane Road/tourer, size unknown, prolly 58 c-t. I can get a VanDessel G&T for a good price, but it's a 58 c-t w a 57c-c TT. I'm just shy of 6' and have about a 32.5 inch inseam. I'm thinking that even though the VD is a good buy, it may be too big. Any thoughts?? I don't want to spend $500 on a bike that's too big.(frame/fork)
 

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I wouldn't size down for a cross bike. Cross bikes often have high bottom brackets making them seem big (for standover). I think way too many people ride too small cross bikes with cramped cockpits because they don't feel good having minimal clearance, but that's just my opinion. And if you have problems mounting or dismounting a "tall bike" you don't need a smaller bike -- you need a different design with a lower bottom bracket.
 

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Don't race cross much do you? The general rule of thumb is to ride small on a cross bike. It's not that anyone has trouble mounting or dismounting, it's that a smaller bike has a smaller length, thus facilitating getting off and back on. The height of the BB is immaterial, as your seat height would stay close to the same as a road unit (measured center of BB to top of saddle). From the ground, I think my difference is all of 2cm and my seat height on the cross bike is 1cm lower due to the fact that pedals are different and some space is needed to move around a bit.

To reiterate, you cannot correctly size a cross bike by standover or the size of the frame as cross bike sizing is whacky. Go by the top tube length. Some cross bikes are also compact framesets (why, I have no idea as you can't shoulder the thing) as my pictures above show. Standover will obviously be different.

A low BB on a cross bike would be little more than a touring bike with knobbies...
 

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merckx56 said:
Don't race cross much do you? The general rule of thumb is to ride small on a cross bike. It's not that anyone has trouble mounting or dismounting, it's that a smaller bike has a smaller length, thus facilitating getting off and back on. The height of the BB is immaterial, as your seat height would stay close to the same as a road unit (measured center of BB to top of saddle). From the ground, I think my difference is all of 2cm and my seat height on the cross bike is 1cm lower due to the fact that pedals are different and some space is needed to move around a bit.

To reiterate, you cannot correctly size a cross bike by standover or the size of the frame as cross bike sizing is whacky. Go by the top tube length. Some cross bikes are also compact framesets (why, I have no idea as you can't shoulder the thing) as my pictures above show. Standover will obviously be different.

A low BB on a cross bike would be little more than a touring bike with knobbies...
"Don't race cross much do you?"

That's really not necessary. Are you replying to my post? Are you an A/ Cat 2 in cross?

In many ways I agree with you about the BB height. I feel comfortable mounting and dismounting on a bike with a high bottom bracket -- but some riders, especially beginners find it difficult to mount and dismount a bike with a high BB since the seat (relative to the ground) is higher than what they are used to. I too believe in sizing by the top tube and not standover height.

However, I disagree that cross bikes should be sized down and I don't believe shorter bikes facilitate getting on and off the bike. Cross bikes are actually much longer than road bikes. This is usually accomplished with longer chainstays. In theory, going shorter on the top tube and front center of a cross bike isn't a bad idea -- there isn't as much of a need to have a stretched flat back position in shorter high power events.

I understand that some racers like to size down their crossbikes. But the traditional camp, which has its own reasons, believes otherwise.
 

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OK Basically

It doesn't matter what the NOMINAL size is. All that matters is the actual dimensions.

I ride a sz S/M road bike with a 53.5 cm effectual toptube . I rode a 52cm Redline with a 53cm top tube. I ride a size 54cm Gin and Trombones with a 53cm toptube.

So I have a 'slightly' shorter toptube on my cross bike, but that's the way I like it. Others may differ.
 

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merckx56 said:
Don't race cross much do you? The general rule of thumb is to ride small on a cross bike.
I've been racing for 3 seasons. I don't size down. I think you'll find many folks around this forum don't size down either -- and there are plenty with lots of racing experience. What I suggest is to size by tt length with an eye on not getting a bike that's too tall such as Ridley geometry.

I bought into the size down thoery when I startde out. That frame is a distant memory. I'm more comfortable on "same size" cross bikes and I'm pretty smooth on the remounts ...
 

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Gripped said:
I've been racing for 3 seasons. I don't size down. I think you'll find many folks around this forum don't size down either -- and there are plenty with lots of racing experience. What I suggest is to size by tt length with an eye on not getting a bike that's too tall such as Ridley geometry.

I bought into the size down thoery when I startde out. That frame is a distant memory. I'm more comfortable on "same size" cross bikes and I'm pretty smooth on the remounts ...
Ditto here, don't size down.
 

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find a fit

I'm an equal TT length guy as well. (or close to equal) and make up the difference with a slightly shorther stem and also flipped.
my road bike is 72c 'reach' (Top Tube and Stem) (60+12) but bars have more drop as stem is set - rise
my cross bikes are 71.5 (59.5x 12) and 71 (59x12) and bars are higher due to + rise
rest of distance seems to be made up by ST angle, saddle fore aft.

road bike has a 60 C-C ST, crossers are 59 and 58 C-C St's.

You say your Ridley Roadie has a 56.5TT your crosser is 55, I'm having a hard time figuring how they can have the same cockpits. Are the ST angles radically different? are you running a 100 stem?
 

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tobu said:
"Don't race cross much do you?"

That's really not necessary. Are you replying to my post? Are you an A/ Cat 2 in cross?

In many ways I agree with you about the BB height. I feel comfortable mounting and dismounting on a bike with a high bottom bracket -- but some riders, especially beginners find it difficult to mount and dismount a bike with a high BB since the seat (relative to the ground) is higher than what they are used to. I too believe in sizing by the top tube and not standover height.

However, I disagree that cross bikes should be sized down and I don't believe shorter bikes facilitate getting on and off the bike. Cross bikes are actually much longer than road bikes. This is usually accomplished with longer chainstays. In theory, going shorter on the top tube and front center of a cross bike isn't a bad idea -- there isn't as much of a need to have a stretched flat back position in shorter high power events.

I understand that some racers like to size down their crossbikes. But the traditional camp, which has its own reasons, believes otherwise.
The answer to your question is YES, I do race A in cyclocross. Go to a cross race and look at the bikes. They are all on the small side for those who are racing them.
 

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For what its worth, I too ride the same TT length on every road, rain, cross, commuter, trainer bike I own. All with the same stem length too. I think the whole size down (frame) & run your seat a little lower for cross guidlines are a bit out dated. Thats just me personally (& just about everyone I asked as well).

DP
 

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merckx56 said:
The answer to your question is YES, I do race A in cyclocross. Go to a cross race and look at the bikes. They are all on the small side for those who are racing them.
Ummm -- maybe in small races where half the riders are ex- mtber's, but I think if you look at cross bikes from well established areas like the West, Northwest, or New England I don't think you'll find it standardized that racers size down their cross bikes. This doesn't seem worth arguing since I admittedly haven't gone about measuring everyone's cross and road frames and conducting a poll. All I know is that there are many racers out there who don't size down their cross bikes but I guess it's different in your experience.
 

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Top Tube Length

I'd go by the top tube length you ride on your road bike. Running a smaller frame size will probably cramp you up a bit and force you to use a longer stem. Generally you want to sit up a bit more on a cross bike so you might just flip the road stem to give more rise or roll the bars back a bit to bring the brake hood up higher. We design our frames with a slight slope in the top tube to give you a little more standover. I'm 5'11"/32" inseam and I ride a 56cm TT. Our bottom bracket are also not very high. Our research came up with the reason cross bikes had high BBs was that back in the good old days of toe straps, cross riders rode a lot on the back of the pedals and the higher BBs gave more toe clip cleareance. Can anyone verify that? My bike has 72mm of BB drop and I had no issues with pedal/crank clearance and it handles great.
 
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