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Chainstay length.(13 posts)

Chainstay length.Len J
Jun 26, 2002 4:46 AM
How big a difference does one inch of Chainstay length make in the ride?...in the handling?....In the shifting (triple)?

I noticed, while going thru the Serotta site, that the difference in chainstay length between thier standard geometry bikes & their touring bikes, was around 1 inch (for a 57). I was kind of surprised by this as I expected a much bigger difference. Does this 1" change the ride significantly? I realize that, because of the different angles, fork rake etc, that the wheelbase is different by more than one inch which overall changes the ride significantly but I was trying to understand the effect of this one change specificially.

So, as I ramble, if you were to compare a regular CSI with a custome CSI where the only difference was a 1 inch difference in chainstay length, how different would the ride be?

Thanks in advance for the insight.

Len
re: Chainstay length.Nessism
Jun 26, 2002 5:15 AM
Longer chainstays will have a subtle effect in the following ways:

- Change the weight distribution slightly toward the front

- Add a small measure of compliance to the ride in the rear

- Lengthen the wheelbase slightly slowing handling

- Reduce the tendency to get crossover chain rub

I don't think these changes are like night and day, but they will be noticeable to a sensitive rider.

Ed
Miatas and minivansSpoke Wrench
Jun 26, 2002 6:01 AM
How you plan to use your bike makes all the difference. The longer chainstays on a touring bike allow you to carry panniers far enough back that you don't hit your heel and the center of gravity is still in front of the rear axle. One inch, if it makes the difference of going over center, can matter a lot.
Depends on what you do with that inch.MB1
Jun 26, 2002 6:52 AM
It is likely going to give you a lot more tire clearance:
Fatter tires can give you a smoother more stable ride.
Room for fenders letting you ride on wet roads.
Better shifting over a wide gear range since chain deflection is reduced.

The whole point being to have a more comfortable all day ride at the cost of a tiny bit of weight and some equally tiny bit of slower response.

Rivendell bicycles has a lot of discussion for this and other similar frame design issues on their web site.

You did notice that all our bikes had long chainstays didn't you?
Yep.Len J
Jun 26, 2002 7:14 AM
That's what got me thinking about it.

I don't race, but do like speed, including high speed training rides. I do like a responsive bike, not as much concerned about steering responsiveness as pedaling responsiveness. I actually like climbing (even though I don't do much of it in the Flatlands). I do like long rides & do intend to do more multi-day organized riding. And finally, I want to replace my Trek with a better fitting bike (if I ever get a job).

My Dilema is that the bike I think I need to do these things is a mix of several different types of bikes. I like the idea of a touring geometry, but don't see the need for Cantilever brakes (and the weight that goes with them). I want enough clearance for wider tires, but no more than 28's. (as opposed to the 35's that seem to be what touring frames are designed around). I love the way the Trek responds to input & the smooth ride & the light weight that I do notice when climbing.

Is there a bike that fits all these things? My fear is that, while I know I can get these things if I go custom, will I end up with a bike that is weak in all of them?

Enough ramble, the way you and Miss M have your bike's set up seems somehow right to me, I'm just worried about the weight.

Len
Don't be a weight weenie!MB1
Jun 26, 2002 9:05 AM
I was thinking your bike might be a little small for you. You were pretty much in a racing position (are you comfortable in the drops? We can ride in 'em all day long).

Waterford and Rivendell make the kind of bikes we ride-with and without cantis. I like cantis for the power. If you are ever back in DC perhaps you can borrow my brother in laws Waterford. Outght to fit you to a "T".

I'd own one but I know how hard I am on my bikes finish-shame to own such a beautiful bike if you aren't going to take care of it. You seem to take care of your bike.

Both makers offer full custom bikes with a long wait (Rivendell has a very long wait) or semi custom right now. Check out these links for the frames I would ride.

http://www.rivendellbicycles.com/html/bikes_rambouilletframes.html

http://www.waterfordbikes.com/models/pframe.htm
Why Not? (I need all the help I can get!)Len J
Jun 26, 2002 9:24 AM
I can ride in the drops for extended time. I'm very flexible (Palms on floor with straight legs pretty easily).

Friend of mine just got a Waterfors set up for touring and it weighs 25 lbs. My trek is under 17. I don't think I'm a weight weenie but 8 lbs seems significant to me. Its a beautiful bike but.........

I think you are right that the only way to tell if the extra weight means anything is to ride it, unforunatly, it's hard to "Stumble" on a correctly sized bike to try. Your idea about your B-in-Law's bike sounds great. The real fear, for me, is spending all the money & time & then ending up with something that I don't like riding.

Len
Let's talk weight.MB1
Jun 26, 2002 9:53 AM
So you are thinking there is a 32% weight difference between a 17lb and 25 lb bike with the natural huge performance difference. Wrong, wrong, wrong. Bikes don't ride themselves.

Say you weigh 160 lbs.
Put on 8 lbs of clothes and helmet.
Carry your wallet, keys and junk 1 lb.
2 bottles, pump, tool kit, & food. 4 lbs.

Total plus your 17 lb bike = 190 lbs
Total plus the 25 lb bike = 198 lbs
Wow what a difference 4%. I noticed you rode with a camelback so add a few lbs to the total but not much % change.

Now if the rotating weight on the 2 bikes is the same it is gonna be really hard to find much difference. If you ride with a steady effort it gets even harder to find much difference.

Rotating weight starts from the outside in. Tires-tubes-rims-spokes-shoes-pedals-cranks-cassette-chain-hubs and bb all move. (Don't forget your spokes, rims and tires also have aerodynamic properties).

Now racers are changing speeds all the time and light stuff is right for them. Some of the slowest rides I ever had were while racing long races as a Senior Cat 2. Sometimes we would just poke along maybe not even at 15mph. Ah, but when the hammer came down....

Us older folks are not about to ride that way. We want to enjoy the whole ride not just the thrill of the finish. Somehow Miss M and I have gotten a bad rap as "Fast" riders. We aren't, we just don't stop much and finish sooner than a lot of folks who are a lot faster than us. We do what we do well.

Notice we run good wheels and tires? That is where you are going to notice any weight difference. I can really tell when I put heavy tires on my SS-what a change.

Get a nice comfortable, stable, durable frame and parts. Spend your money on wheels and tires for performance.

OMO
No fair arguing rationally!Len J
Jun 26, 2002 10:06 AM
Why are you bringing facts into an emotional discussion?

All kidding aside, I know all this, and I'm glad to be reminded of it, but I do worry about buying a "Pig' that I won't enjoy riding.

I'll be bringing my 21+ lb Lemond B/A with a triple this weekend. It definately doesn't climb as well as the Trek, (although with the triple I can climb more hills longer which is why I'm bringing it to the tour), the Trek just feels like it takes less effort to get it up a hill.

Old habits die hard, but I'll get there eventually. Good thing I have time before I pull the trigger.

Thanks

Len
maybe their Road Sport RS-22 would split the differenceTig
Jun 26, 2002 11:05 AM
The Waterford touring may be too much of a deviation for you. You friend's bike might use the heavier Reynolds 531 tubing and not the 853. The Road Sport RS-22 may be worth checking out. It is designed more for centuries than touring or racing. The chain stay length is about in the midway point between their racing and touring models.
http://www.waterfordbikes.com/models/rs/pirs.htm

You may also want to check out the relaxed, longer wheelbase geometries that Merckx and Hampsten bikes use. They retain their racing edge, but not at the cost of comfort or stability like many American criterium frames. I love the lower BB, lengthy chain stays, and longish TT of the Merckx Century geometry. Any custom frame I'll get in the future will be based on it.
Yep.dzrider
Jun 26, 2002 10:43 AM
With most of the same desires I wound up with a Jeff Lyon bike from GVH. I've been very happy with its ability to feel good on both shop rides and brevets. The longer wheel base and low bottom bracket give it a very comfortable ride. It's light and stiff enough to help get me up most of the hills in CT on the middle ring. Versatile bikes are possible. It's quite similar in shape to the 1980 Trek "sport-touring" bike I commute on but lots lighter and a little stiffer.
re: Chainstay length.pa rider
Jun 26, 2002 7:20 AM
Not sure if you notice difference for road bikes, but on MTB you have different climbing ability.

I owned, at one time, a few fisher bikes and cannondale that had 16.9 chainstay. When I bought a Gary Klein Pulse, in 1995, with a 16.4 chainstay I noticed I climbed better. I think my gary fisher sugar bike last year had a shorter stay of 16 inches and climb well.

It's like how the other posters said, the weight of your body distribution is the main factor. You also have to take the seat angle into account. I think a 73.5 degree seat angle will give a different chainstay compare to 73 degree.

I nevered notice any road bikes having that much of difference in chainstay lenght when your comparing two or three bikes dimensions against each other. I'm refering to stock bikes maybe the reason.

Emory
re: 1" is a lotcyclopathic
Jun 26, 2002 8:35 AM
take seat angle/offset into consideration. On my 52cm frame the rear edge of the saddle is only 3" forward of rear axle. 1" would increase effective offset by 15-20%.