Tandem Cycling - Granny gear, aluminium or steel???
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Cheetah
06-18-08, 10:21 AM
Hi,
We are going to the Pyrennees mountain for our next trip and I am looking to replace the 30T granny gear for a 26T. The 30T is made of steel but all the 26T I can find are made of aluminium. I am wondering how long an aluminium granny will last considering the extra weight of a tandem. It will certainly be used in all climb as I checked on cyclingcols.com all the cols we are going to climb and many of them average at 8-9% for 3-5 miles.
What you guys think?
Thanks,
Michel
merlinextraligh
06-18-08, 10:25 AM
i think you'll be fine with Al. Most road crank rings are made of Al. An al 26 ring will wear a little quicker than steel, but unless you're riding in really grimy conditions (such as mountain biking, it should still last multiple seasons.)
If you're reallly concerned, make sure you keep your chain clean and lubed, and avoid shifting into the Granny under pressure.
I suspect the aluminum rings could well be of somewhat better quality than the steel one you are replacing. Still you may only manage to get a few years of use out of the thing-depending on how much you use it.
FWIW I have never worn out an inner ring on a triple-true we don't use them much any more but still folks just don't tend to spend hour after hour day after day on the inner ring.
Aluminum grannys wear out pretty quickly on a mtb,but thats in mud use, which may accelerate the wear by a factor of 10.
I would prefer a steel if I were you,but aluminum may do OK. I would test in on a steep local hill before you leave however, to make sure it doesn't fold up.
zonatandem
06-18-08, 04:18 PM
Alu/alloy 26T chainring should do just fine.
specbill
06-18-08, 09:27 PM
Agree.. a new quality alu 26T with a fresh chain will do fine for your trip. Good luck..have fun.
Bill J.
Cheetah
06-19-08, 04:14 AM
The reason I am asking is because a friend of mine went to the Alps last year with his single road bike. He had a new chain, a new cassette and an aluminium 30T on his triple crankset. The 30T was almost never used before that trip. He rode about 500 miles. At the end of the trip, the chain was jumping on the 30T. My friend is a bit heavy, about 200lbs, but it is still much lighter than a tandem. Over the 500 miles, around 40% was done on the 30T. May be his 30T was of a lower quality???????
Thanks for the info. Have a nice day,
Michel