Thigh Master

As I pedaled during our ride yesterday my (captain's) crank arms began to feel slightly loose. Once home I could detect a small amount of play in the them. We have a 1997 Burley Duet. Is this something a bottom bracket getting tired or just time for a little tightening?

VaultGuru

Don't know what type of cranks you have, but it could be that the crank arm needs to be tightened a little bit. Is it a side to side movement? Is your transfer chain getting loose too? If so, there are two 5mm allen heads on the top of the BB on either side of your down tube. You need to tighten your chain, center the BB and tighten the two allen heads. Otherwise, I'm out of my league on the knowledge base. TandemGeek will probably know.
Cheers

twilkins9076

I'm assuming your '97 is the same as our '05. You should have two set screws on the top of your bottom bracket. If they have come loose, you might feel some side to side play, but your most likely symptom would be a loose timing chain because that eccentric is going to want to turn without the set screws holding them in. If those set screws are tight, check to see that your cranks are tight. There should be a bolt in the middle that actually screws into the arms of the bottom bracket. The only time I've ever experienced lone of those coming loose, it was on the drive train side of my commuter, and the way I noticed it was there was a very pronounced wobble of the chain rings. I suppose if it were loose on a tandem, you should be able to see a significant chainring wobble on either side.

TandemGeek

As already suggested, the first things to check are the easiest:

1. Make sure your eccentric isn't loose
2. Make sure your crank arms are firmly pressed onto the square taper spindles
3. Make sure your crank-arm bolts are properly torqued

If you've checked all of those things and there's still some play in the cranks then it may be time for some new bottom bracket bearings. Any idea how many miles are on that tandem?

Anyway, pre-2003 Burley's are a bit unusual in that Burley used it's own proprietary bottom brackets: pressed-in assemblies with cartridge bearings that are held in place by snap rings. Interestingly enough, they tend to outlast a lot of the more conventional sealed and non-sealed threaded bottom brackets used by the other tandem makers and only the bearings need to be changed when things get sloppy. The trick these days if you haven't ever replaced pressed-in bearings is finding a bike shop that has. In some cases, machine shops are a better choice. Regardless, it's actually not all that hard. Here's a link to a pretty detailed posting from a Hobbes list member that describes the process on a similar vintage Burley Rock & Roll: https://search.bikelist.org/getmsg.as...10009.0311.eml

Thigh Master

Thanks everyone. Doh! Just needed to tighten the two set screws!