T.E. gearing and chain length help needed.
 

I'm riding an early 2000 T.E., which I purchased used a few years ago.

It came equipped with 24-42-52 rings and an 11-34 8spd. cassette all served by Shimano Deore XT derailleur and shifters. It has a Terricycle idler for return chain management.

My problem is this: I can't seem to get the chain to the correct length and apparently neither could the previous owner. It's either too short In the 52-34 configuration or too long in the 24-11 configuration. I'm currently running with the too tight scenario and hoping I remember not to shift into the 52-34 gear combo.

I've been in discussion with my LBS in an attempt to rectify this issue. I really like the gearing I have now so I would like to find a way to make it work, if one exists.

We looked up Shimano rear derailleur with 36 tooth capacity but they had insufficient wrap (45 tooth vs. my 51 tooth). We also looked at some chain tensioners that mount to the chain stay wondering if one of those might give me enough clearance to use my 52-34 combination with my current chain length.

We did not look up any SRAM derailleur since I have the Shimano trigger shifters but if SRAM has components that will sort this out then I am willing to spend the money to change components.

Have any of you successfully used this combination of gears and found the components to allow proper chain length throughout the entire gearing range? Advice please??

Wow. Good question. No idea. A 24X34 gear? I couldn't keep my bike upright at that gear.

That's my gear arrangement:
http://home.comcast.net/~jeff_wills/...-grr%20006.htm
http://home.comcast.net/~jeff_wills/...-grr%20008.htm

The 24/34 allows me to climb 15% hills with a touring load. It's barely faster than walking, but if I wanted to walk I wouldn't be on my bike.

The answer to the chain length question is that the chain should be long enough to go around the big chainring/big cog combination and through the derailleur. You probably won't be using the small chainring with the smallest 4 or 5 cogs- shift up to the middle chainring and big cog when the hill allows it.

You should never make the chain "too short". You might think you won't ever shift into the big chainring/big cog combination, but some day you'll be at the end of a long day, tired & dopey & forgetful. That's when you'll shift into the big/big... if the chain is too short, you'll be lucky if it just jams. You can bend or break things by forcing this shift.

What Jeff said. Longer answer: That gearing goes beyond the capacity of your rear derailleur, so you can expect that if you have sufficient chain to wrap around a 52/34, then if you ever use about your 24/15 (or smaller in back) you're going to have slack chain. That's why the older EasyRacers had a pair of jockey pulleys where your return idler is -- to take up more slack. Just don't use your small ring with any more than the largest 3 or maybe 4 gears in back. If you do, you're probably still OK even though it might look bad. Certainly better than not having enough chain for your 52/34 and accidentally ripping the derailleur off the frame, destroying your rear wheel in the process!

Thank you all for your prompt and informative responses.

I'm going to size the chain long enough to handle the 52/34 combination thus eliminating the chance of accidental damage if I happen to shift into that combo.

I do use the 24/34 on a couple of hills that I frequent in my neighborhood. I'll be both practicing my shift technique to elliminate chain slack and shopping around for an original T.E. chain tensioner or a reasonable facsimile of one.

It's so nice to have a plan...

24/34 is fine. Where you'll have slack chain is if you ever try to use your 24/11 or 24/13. There's really not much point in using those two anyway, since they're within the range provided by your middle ring.

I've been contemplating switching my bike to that combination. I currently have a 52-42-30 with a 9-gear 11-32 cassette. I have two idlers on my bike for both directions of chain travel but they are fixed. Now I'm wondering if I should keep the cassette I have and only change the ring to 24...OR...(and this might help with the OP's issue)...switch to a 26 ring and maybe the 11-34 cassette might be more doable. I have the same rear derailleur by the way.

I guess I should add that I cannot imagine ever needing to use the small ring/small gear combination so perhaps this is moot.

It's two teeth difference either way, so it is moot* point. Either way, there's very little change in derailleur geometry or requirements.

*One of my dad's colleagues was Dr. Lloyd Moote. He was fond of making Moote points.