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Chain Ring Compatibility - A Problem 23 Years in the making

9K views 45 replies 8 participants last post by  Lombard 
#1 ·
I have a 23 year old Canondale T700 touring bike that had custom components put on it when I bought it in 1994. It was originally an Ultegra 8 speed rear with an RX100 Triple Front Crankset. The front chainrings are Shimano SG 52, SG E-42 and E-30. Front derailleur is Deore LX.

I replaced the rear cassette, derailleur and shifters with Ultegra Derailleur, 10 speed 11-28 and Ultegra 10 speed shifters about 5 years ago. Recently (4500 miles later) I ham having massive chain slippage to the point the bike is un-rideable. The chain was severely worn, so I replaced that first but same issue. When I look at my 42 tooth middle chainring it looks rally badly worn with a few teeth worse than others. I do not believe the derailleur is bent although it could be worn, but it seems to be slipping on the front under pressure.

I cannot figure out what chainring might work on this old setup. Or even whether a new crankset could be put in - I am new to this part of bicycle maintenance as I haven touched it in 23 years. I have been searching for information but this is so old I am not fining anything even on Sheldon Brown's pages.

I have a new Salsa Warbird gravel bike but would like to get this old one ride-able enough to use even on a trainer. What can I buy/try ?
 
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#2 · (Edited)
Finding a new middle chain ring could be like finding a needle in a haystack. You will most likely need to replace the whole crank set.

Which crank set will work for your bike will depend on what type of bottom bracket you have. Since your bike is a 1994, can I assume you have a square taper BB? If that is the case, you will probably need to go with a crank set made by Sugino:

Sugino XD600 Triple Cranksets | Jenson USA

If you want Shimano, you will need to convert to a Hollowtech II BB. This is possible, but it's a juggling act to get all the adapters correct in order to get the correct chain line. You could try this, but it could result in nothing but endless frustration.

Edit: Apparently Shimano does make a square taper triple, but it's an entry level one. It comes in both touring and mountain gearing options. Price is right:

Shimano Acera M361 Square Crankset | Jenson USA
 
#4 ·
Your crankset is from the 8 spd era & I assume that you were running an 8 spd chain with this original setup. When you went to 10 spd, did you keep that 8spd chain to run with it as well?? If you did, I'm not surprised that you have chain slippage issues.

Most definitely, you need a new cassette & chain as well. I wouldn't bother finding 8 spd chainrings for a 10 spd drivetrain because although I'm sure it would shift, it isn't doing so optimally & you're just shortening the life span of your components. Its better overall to keep everything of the same generation. I'm kinda amazed that you have the original crankset & bottom bracket to be honest.

You should replace the crank with either a 9 or 10 spd one. As for the bottom bracket, any matching the crankset in English/BSA will do. For example not knowing your leg length, here is what I was able to find on short notice: FSA Gossamer Triple 30/39/50 MegaExo Crankset 172.5mm NEW IN BOX! | eBay

Replacing the entire crankset is cheaper than replacing all the rings because although your 42 is the most worn, that worn chain has already done its work on the other rings to warrant their replacement as well. Good luck.
 
#5 · (Edited)
Your crankset is from the 8 spd era & I assume that you were running an 8 spd chain with this original setup. When you went to 10 spd, did you keep that 8spd chain to run with it as well?? If you did, I'm not surprised that you have chain slippage issues.

Most definitely, you need a new cassette & chain as well. I wouldn't bother finding 8 spd chainrings for a 10 spd drivetrain because although I'm sure it would shift, it isn't doing so optimally & you're just shortening the life span of your components. Its better overall to keep everything of the same generation. I'm kinda amazed that you have the original crankset & bottom bracket to be honest.

You should replace the crank with either a 9 or 10 spd one.....
It is true that you need a 10-speed chain to work with a 10-speed cassette. However, an "8-speed" crankset will work fine with a 10-speed chain. As we went to more speeds on the cassette, chains had to become narrower. Now you are probably thinking "ahhh, so my 10-speed chain will be too narrow for my rings". But as chains became narrower, they only became narrower on the outside so they would fit in between the smaller clearances of each cog on your cassette. The width of the inside of a 10-speed chain is the same as an 8-speed chain.

Yes, you will see crank sets that say 8-speed, 9-speed, 10-speed, etc. As far as crank sets, those numbers only matter in marketingland. The only number of speeds you need to be concerned with on crank sets are 3-speeds for a triple, 2-speeds for a double........you get the idea.

As for the bottom bracket, any matching the crankset in English/BSA will do. For example not knowing your leg length, here is what I was able to find on short notice: FSA Gossamer Triple 30/39/50 MegaExo Crankset 172.5mm NEW IN BOX! | eBay
Wrong. Finding the right sized BB is more than just getting one to match the crank set you are installing. It's not that clear, cut and dry. You need to get the chain line just right or it will not work.
 
#12 ·
I guess for $20 and free shipping, it's worth a shot. Just be sure to get the right BCD for your crank.
 
#17 ·
1983 Cannondale ST-500 tourer and a 1984 Raleigh Olympian road bike.... I have been through some of this.

Easiest by far is going with a square-taper BB and then buying (unfortunately Low-end) new crankset or doing EBay for NOS. There is a lot out there---it just takes a lot of patience to get good deals on good merchandise.

I have switched one square-taper BB bike to a HollowTech BB successfully, but the Hollowtech is wider ... I went from a triple to a double so it worked, but I am not sure what a triple would be like ... I'd imagine pretty wide.

Not to say that to wouldn't work. It might not have a scientifically optimal chain line ... but it still might ride fine. Trial and error .....

One issue he will face will be rear spacing, which will probably be 126 mm .... and on a Cannondale, stretching that can be a pain. That means that he has less room to go wide up front before tweaking the chain in the back ... its only a couple mm difference, but it will make cross-chaining noisy (not that any one cross-chains, right? ;) ) and if he goes too wide he might hit the chain stay.

But ... none of this is rocket science. I have run a number of different cranksets on both bikes .... the Cannondale is pretty forgiving (it has a modern 48-38-28 Shimano crankset with a square-taper BB on there now and works wonderfully.)

Unless he really demands historical accuracy, he can get all kinds of stuff off EBay which will keep his bike running for a long time.
 
#18 ·
If you replaced the chain after 4500 miles and not the cassette, I'd say that could be your problem.

The few worn teeth you described was how some rings were made to allow easier shifting. But I can't see it from here.
 
#19 ·
If you replaced the chain after 4500 miles and not the cassette, I'd say that could be your problem.

That would be a problem as the chain and cassette eventually "marry each other". However, I believe the OP's slipping is in the front. And yes, as few chain ring teeth that look worn are indeed that way on purpose to aid upshifting. Now, if they all have sharp points or look like shark fins, that is definitely wear.
 
#23 ·
I have been reading all of these posts with much interest. One clarification - when I said I had not touched the bottom bracket, that did not mean it has never been serviced. I rode that Canondale a lot of miles and took it in regularly for maintenance over the years, including the bottom bracket on at least 2 occasions I can remember. I am trying to learn more about bike maintenance for fun really. That is why I tried the 8 to 10 speed upgrade on my own (the old 8 speed Ultegra 600 shifters wore out).

I do confess to be totally confused about bottom brackets and crank sets despite reading all of this. The archive site linked above says my bottom bracket is 122.5 mm long and I assume that is the length I would look for if I was to go that route at some point (if I understand it correctly). Diameter and threads have to match as well. I can measure chain line with my calipers pretty easily but would have no idea where the new bottom bracket would leave me on chain line... Again thank for your help - wasn't trying to start an argument - just trying to learn from everyone.
 
#24 ·
The archive site linked above says my bottom bracket is 122.5 mm long and I assume that is the length I would look for if I was to go that route at some point (if I understand it correctly). Diameter and threads have to match as well.
122.5mm is the length from spindle end to spindle end. Yes, that is what you would have to match. Threading is easier. You have a standard English threaded 68mm which is the measurement from thread end to thread end. This BB is what is referred to as a 68x122.5 square taper BB like the one below:

https://www.amazon.com/Shimano-Squa...ywords=square+taper+bottom+bracket&th=1&psc=1

If/when you need to, the Shimano UN55 BB above is a good one to replace it with. This one has a steel bearing in it rather than the Teflon cartridge found on lower end BBs.

In order to replace this, you will need some special tools - a special socket to remove the BB as well as a special crank puller.

Very important: If you decide to replace the BB (or for that matter, any threaded BB) be sure to put plenty of anti-seize compound on the threads before installation. This will prevent any creaking as well as prevent a plethora of swear words coming out of your mouth when the time comes that you have to take it out again.
 
#26 ·
Foer $50 (and probably $20 resell, after shipping, if it doesn't fit) trying the FSA triple is a tempting idea ... depends how tight cash is.

I would switch all my bikes to Hollowtech if I could ... for different reasons, I don't think it is possible or profitable with a couple ... and frankly square-taper is about as bulletproof and as simple as can be. It is heavier, and it does impose some limits on crankset choices .... but I have stuck with it in a couple instances because it is so simple.

I guess if it were me, I would look at the BB and see how much space there is between the edge of the BB shell and the crank arm. If it is more than about 3/8 of an inch you might have space for outboard BB bearings ... i.e. Hollowtech or any of its competitors (GPX, Mega Exo.).

if it were me I would be Sorely tempted by the $50 FSA triple .... so tempted that I am actually going to the site and looking at it as soon as I post this.
 
#29 ·
Square tape was ok for its time. I was racing on it when I first started out, so I always took it apart at the end of the season to repack it. Frankly working on it was a PITA though. I've gone through Superbe Pro & a bunch of Campy Chorus cranks since then. I even have a brand new, old stock Chorus lying around somewhere.

Nothing though beats the outboard bearing design like Hollowtech, GXP, Mega-Exo or Ultra-torque for ease, durability & simplicity. Minimal tools to install it & once installed forget about it until it wears out. I've gotten 3 seasons out of one of my winter bikes that I ride through total crap & often times I don't/ can't be bothered to clean afterwards. 3 yrs of use with zero maintenance....life is good.
 
#27 ·
I looked at that triple .... a very good deal. However, note that Shimano uses (I think) 24 mm spindle and MegaExo is 19 mm. This means you will always be using FSA cranksets .... which is fine. I have one on my Fuji and it is as good as Shimano in my opinion/experience.

I won't be bidding against you because I don't want to put a triple on my Fuji and i would want to have the option to switch between the double and triple on the other bike, my tourer/commuter/grocery bike.

Only half an hour left, so snatch it up.
 
#28 ·
For what it's worth I just picked up a new, but unboxed, Shimano Tiagra triple on Ebay .... whenever it arrives and when I have time I will stick it on the frame which has the double now and report back. Might take a while as I am busy ... and when I get free time, I really need to do more miles than more wrenching.
 
#30 ·
So. I have now installed a new rear cassette ($40), that I always knew I would likely need, and the middle chainring ($20). And I basically have a 1x10 bike :). Even before all this I had issues with the front chainrings and the spacing for shifting because of the spacing. An old 8 speed front using narrow 10 speed chain - it falls between the top 2 rings for example. Now it seems even worse at that problem. Very hard to get it to be on a ring. So $60 in, trying to figure out the bottom bracket / new crank set issue discussed above.

Best I can actually measure mine, Chainline measured to the inside of the middle ring is 40.2 and to the outside is 43.5. The inner 3rd ring actually is slightly over the top edge of the bottom bracket.

This link gave me some information on the RX100. Looks like Chinline is suppsoed to be 45 - or maybe 43.5....
Shimano Front Bike Chainwheel Features Comparison - the Buyer's Guide, 2015

Now - how do I figure out what to buy that will work with my set up and not spend much money... . Maybe i need a new front derailleur to help with smaller chain... .
 
#31 ·
I am no bike mechanic but it sounds like the derailleur, not the chain, is the problem.

The chain is like 3/128 of an inch narrower on the outside and the same width inside---the side plates are thinner. Therefore even if the chain is narrower, it will fit the chainrings ... and itf it is 3/128 too far to one side or another, it should still slide into place.

More likely your front derailleur is misadjusted or your shifters are pulling the wrong amount of cable.

I will read back through the trad when I have more time ... but i can assure you if the derailleur is dropping the chain between two rings ... the derailleur is dropping the chain between two rings. 11-speed chain should work fine about anywhere.
 
#32 ·
I see you are using an 8-speed Deore derailleur? And I assume 6700 Ultegra shifters?

I Think they should work together .... you should look it up online,. Google "cable-pull per shift---6703 Ultegra" and "cable pull per shift... 8-speed Deore front derailleur:" or something like that.

I think the issue might be derailleur set-up. If you can't set the front derailleur up to hit the inner chainring .... why not? if it won't swing in far enough, you might need a wider BB. it could be a weak spring, or a bent mechanism or just the High-Low stops are misadjusted.

Play with height above the chainring too. 52-42-30 is pretty standard, but I don't think the Deore was designed to handle more than 48 teeth. Did the front derailleur work perfectly before all this started happening?

No, reading back I see it didn't. And it seems all your front-shifting problems started when you went to the Ultegra shifters.

Could be cable-pull, could be derailleur set-up. Could be chain, but I honestly cannot imagine how or why. The chains are so close is overall width .... I know your bike isn't failing to shift over 1/64th of an inch.
 
#33 · (Edited)
Well - I have things pretty bollixed up now.... my lack of repair skill set is shining through :mad2: . So have one side of the crank removed, but the other side is stuck solid. Remover screwed in and then when I tried to remove - instead of pulling the arm, it ripped all the threads out.... So now I have to get it off some other way which may involve mass destruction.

Ultimately now I need to replace crankset which I was headed to in trying to remove the old one. This $20 deal is now over $70 and no crank/bottom bracket bought. :cryin: Thinking about this crank (or one similar to it - maybe a Tiagra if I can find one): https://www.ebay.com/itm/Shimano-10...e=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

https://www.ebay.com/itm/Shimano-10...RK:MEBIDX:IT&_trksid=p2055119.m1438.l2649Will it work if I get a Hollowtech II bottom bracket ? I have reread all of the posts in this deal and still cannot figure it out :)

And converting to a double would be a good option too - not touring on this bike any more - mostly will be trainer and road when I don't want to ride my Salsa Warbird and its bigger tires.
 
#37 ·
Comments from a bike mechanic:

All the concerns about cranks being "too wide" or whatever are totally off base. With Hollowtech cranks the chainline is guaranteed to be in spec because the spindle is built into the crank. There is no fudging - if you frame isn't compatible with the crank it won't even assemble.


As far as "modern" equipment goes, none of the newer types of cranksets are actually more durable - Hollowtech type technology is there to lower weight by substituting a big tube for a narrow solid spindle. The old square taper BBs and cranks will usually last just as long if not longer.


For the OP, it sounds like you have pretty much destroyed every cog and chainring on your drivetrain by using an excessively stretched chain. You'll have to be the judge. So if you think that just a 42 chainwheel and new chain will fix it, great. Such a chainring should be super easy to find for that type of crank. If not, find a crank/bb combination that suits your needs and buy them together. They won't be "too wide", they will be exactly as designed for a standard drivetrain. Get a Hollowtech or a square taper with the manufacturer's recommended BB spindle length/type.


For crank pulling issues, not only do you need to insure that the bolt AND washer were removed from the crank, the puller needs to be very firmly cinched down into the crank threads with a wrench before the extraction starts.
 
#38 ·
Comments from a bike mechanic:

All the concerns about cranks being "too wide" or whatever are totally off base. With Hollowtech cranks the chainline is guaranteed to be in spec because the spindle is built into the crank. There is no fudging - if your frame isn't compatible with the crank it won't even assemble.
I have to question this. I bought a Deore touring crankset to convert my old hybrid from square taper to Hollowtech II. It installed just fine, but chain line was out of wack - chain slipped like crazy!

I then tried the same conversion on a different bike, an older touring bike. Same thing! Installed just fine, but wouldn't play nice.
 
#39 ·
This has been an attempt by me to learn more on an old bike that I wanted to keep despite dropping the cash for a new Salsa Warbird that I ride every day (while swearing I wouldn't waste money on my 23 year old Canondale...). I did admit to not being a bike mechanic.... (My Salsa gets it love from the Bike Shop Professional).

That said, last night I completed the install of a used Ebay Shimano FC-5703 Triple Crank on the front with a Hollowtech II Bottom bracket it came with. While I still have some questions about some potentially missing O-Rings or washers, I took it out for a spin after some adjustment on the front derailleur and it seemed to work wonderfully with the new Chain and new 11-28 Ultegra 10 Speed Cassette. All more money than I wanted to spend, but what the heck - once you start a project, its hard to restrain yourself.

I didn't trust it enough to ride this morning on my morning ride in the dark (by myself) but plan to ride it some this weekend just to check it all out.

In the words of Queen, "And bad mistakes - I've made a few..." But I got it all off and new/used back on with only a few destructive techniques that would be considered unapproved. Still want to better understand the spacing comments/thoughts/suggestions above, but chain line seems good and it works in all sprockets and gears so far. Thanks for all your help - I will probably be back with spacer questions on this specific crankset....
 
#46 ·
Nope. Derailleur is not interfering.
 
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