jonny7

Hi all, I've decided to go 10sp on my favorite CV bike. The bike had a Dura-Ace 7400 groupset, I'm changing only the cassette and the RD. I had wheels that were already somewhat modern, with Shimano WH-RS10 hubs.

I've successfully installed the wheel with a 6700 cassette without having to cold set anything. But now the last sprocket looks awfully close to the chainstay. This is my first attempt at modernizing so my judgement might be off a bit. Does this look too close? And would a 130 spacing change anything since the skewer kind of tighten everthing in the end?

Here's a not so clear picture, and the links to 2 youtube vids.



Front view :
Rear view:
What do you guys think?

Oh, and if anybody knows where I can find a cable anchor for the DA-7900 rear derailleur, hit me up!

79pmooney

Drape a chain over the cog and chairing, run it through the derailleur and take a look. (You don't need to connect it. Hold the wheel and push the pedal. Does the chain miss the frame? Are you comfortable with the clearance you have? (Is the paint sacrosanct?)

There's probably a number in some book dictating the clearance you "need". I never read it. I find a chain that runs clean is all I need.

Now I am assuming your bike is spaced 126mm. You may find doing the spread to get the wheel in gets old, especially when you flat late in a hard ride. Also, when you stretch the frame, the dropouts go out of alignment. They are now doing their best to bend your rear axle a little. Probably not an issue, but the axle would rather be straight. Bearings will also be a little out of alignment.

02Giant 

If too close, is there room to go down in size on the high gear cog?

blamester

Put a chain on it and see. I have 10 speed on a 126mm frame and it works fine. But I will eventually cold set it because it is a pain if you remove the wheels regularly.

icemilkcoffee 

If you had a 7400 with 8 speed cassette, then it's already 130mm rear spacing.

Bill Kapaun

7400 was only 6 or 7 speed Uniglide type.
7402/3 was 8 speed.

mitchmellow62

As others have said, I'd put a chain on and see if it clears. It looks tight. You may want to take a look at the following thread that addresses modifying a 130 mm 10 spd hub to fit 126 mm spacing: https://www.bikeforums.net/classic-v...b-success.html

Crankycrank

Another vote for just putting a chain on it and making sure it clears in the big chainring-small cog combo in particular. Make sure you go through all the gears just to be sure everything shifts OK in both extremes of cross chaining. Even better is to then go for a ride just to make sure the real life experience of the chain bouncing around and shifting under pressure does not cause contact. If it all works IMO it's best to get the frame cold set and dropouts aligned to prevent stress on the frame and axle. Not cold setting can put some extra stress on the frame that may not cause any issues or could cause a crack in tubing joints that could take years to show up and misaligned dropouts can cause a slight bending in the axle which shortens bearing life so it just makes more sense to set it right to begin with and prevent possible issues. With the old 126mm freewheel hubs, not having aligned dropouts would cause a few axles to break but with a cassette setup broken axles are far less likely but it can still affect bearing wear.

JohnDThompson 

Cold-setting the frame won't change the clearance issue. If you decide the small sprocket is too close to the chainstay, you'll need to add a spacer to the drive side of the axle and re-dish the wheel.

Crankycrank

Agreed but if jonny7 finds there is no issue with chain clearance then cold setting is a good idea.

cxwrench

What? How would that make any difference? He probably has an 11 now. If it's a 12 then he'd have an 11-13 jump. It looks fine to me.

Iride01 

So you have to ask us before you put a chain on it and see? Why are you trying to start an argument. Just put on the chain and what ever else you need, and go from there. Your position of observation is much better than ours.

I will say I'm thinking you have a 126mm rear spread much like my Raleigh Comp GS has. It has more than enough natural spring in the stays to easily spread itself to 130 when I wider hub is stuffed up in it. I never cold set mine. It just doesn't need it for the weight and conditions I subject it to.

jonny7

Thanks for this. Interesting thread!

Obviously no, but there were 1 or 2 things that encouraged me to ask the opinion of wiser mechanics. I like to play on my bikes and I'm learning everyday but this is my first attempt at conversion and I was wondering if I was missing something obvious. This, and also I didn't have a 10sp road chain at hand to test it right away, so before spending money I thought it wasn't a bad idea to ask. And my RD is currently missing the cable bolt so I can't set up the whole thing.

Eventually found a 10sp Deore chain (HG-54) to do the test. I'm assuming the chain is pretty much the same? Here's what it looks like. Seems close but it looks like it's perhaps okay.





And the chain does clear the chain stay. I guess the next step would be a road test.

squirtdad

just remember that the higer number of gears you go, the more aligned every thing has to be to keep the indexing working. I had minimal problems with a 9 speed and just hand spreading the chain to fit the wheel in. When I went 11 speed (different bike) i had it cold set, aligned and derailier hanger adjusted to ensure good indexing

ymmv

KCT1986

Based on the pic, it looks like the clearance between the chain and dropout is about what you would expect for a road bike with 9 or 10 speed cassettes. How the chainstay & seatstay are connected to the dropout may be different for newer frames but nothing you can do to this frame to change that.

As for the thread about respacing a hub for 126mm, that thread entails moving the freehub body CLOSER to the dropout. Don't think that is what you're trying to achieve.

Crankycrank

Looks like you have enough clearance to me but yes, a road test is needed to be sure.

jonny7

I think the derailleur hanger might indeed need to be realigned. It looks like the current position of the derailleur creates a tension outwards which results in ghost downshifting, even if my levers are tight on the frame.

conspiratemus1

In judging chain clearance, remember that the the chain rotates, or "leans", briefly for a instant just as it begins its shift from the smallest sprocket to the next larger. The outer edge of the top of the link protrudes maybe 0.5 mm closer to the seat stay than it did when running on the sprocket. This rotation usually involves just one link. Once the chain starts to climb onto the next cog, the rotation cancels and it of course is now moving inboard, out of the way. So the outward "lean" of the chain is just a flick at the very beginning of the shift while it is still fully on the smallest sprocket, before it starts to move in. If the timing of a particular shift produces maximum rotation in an outer link just as it passes the seat stay, it can catch. The next test shift might involve rotation of an inner link, which won't catch being narrower. So fouling will likely be intermittent when you are testing it. And in real life on the road, it may work nearly all the time then suddenly jam if it is shucking side to side during its passage from the jockey wheel onto the smallest sprocket. It's most likely to jam in the big chainring because on the big ring the chain comes off the small sprocket a tiny bit higher. So always test chain clearance during shifting with the chain on the big ring.

The clearance you need does depend on the size of the smallest sprocket -- the smaller the sprocket, the wider the space available for the chain to lean into before it hits the inward sloping seat stay.

The clearance you have looks OK. On our tandems, I go for the the smallest possible clearance, transferring spacers from the right side to the left where possible, in order to reduce the asymmetry in the wheel. This would be especially desirable for you: squeezing those wide 8-10-speed cassettes into 126 mm of OLD makes a highly asymmetric wheel and I'd be surprised if you don't start breaking left-side spokes or have trouble keeping them from unscrewing and making the wheel wobble. If you have to put a spacer in the right stack to keep the chain from fouling, the wheel will be even more asymmetric.

70sSanO

Worst case is getting a .5mm thick shim washer for the DS. If the wheel currently fits into the dropouts easily, .5mm won’t be a problem.

Had to do that on a bike when I went to a Sachs Aris 7 speed freewheel; even with a 9 speed chain.

And yes, the miamijim thread was all about getting the freehub body closer to the DS dropout. With 126mm Cannondales, that thread was very pertinent for me.

John

mitchmellow62

To say that the miamijim thread only moves the body closer to the DS dropout is true but somewhat incomplete. What he did was rearrange spacers/washers and locknuts to take 2 mm from each side thereby keeping the hub in the same relative position so that the rim/tire remains centered in the stays and does not need any more dish. Miamijim noted that it could only be done with certain hubs. He noted the 8 speed dura ace and ultegra hubs. I did not mean to imply that this could be done with the WH-RS10 but I admit I was unclear on that point. I was meaning to provide information so that if the OP's current approach wouldn't work, miamijim's thread would give him an alternative approach. Of course, it would require purchasing an appropriate hub/wheel.

70sSanO

That is true. I have studied that thread since my Cannondale is stuck at 126mm. While there is some benefit with the spacers, the real width savings is in the locknuts. I have collected a few very thin locknuts for this purpose.

I had planned on using a FH-7700 and reduce the OLD close to 126mm. From comparing FH measurements, I believe the 7700 matched the measurements of the DA FH-7403; but it has been a number of years since I looked into this. Also the locknuts on the 7700 are very thick.

In the end, I swapped out the 9 speed 7700 titanium freehub body for one off an XT 732 and I’m running a 3x7 which is serving me well.

John