new DA compact - ring choice..?

maddog 2
maddog 2 Posts: 8,114
edited November 2008 in Workshop
anyone know if you can fit other rings, such as TA, older Shimano ones etc.

The standard setup is only listed as 34/50, and the big ring looks different from existing designs, with the bolts not visible from the side.

Shimano website is the usual flash stuff but v. little info
Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer

Comments

  • robbarker
    robbarker Posts: 1,367
    The outer ring is threaded for the bolts that hold the inner ring on. In theory there will be no problem attaching a 36 inner from TA as long as the bolts are the right width apart (bolt circle diametre or BCD in the jargon), although the spider arm pattern will also have to be compatible if it is recessed for the inner ring, and the inner ring will have to be roughly the same thickness (or thinness).

    The fastners are titanium as well so make sure the threads are spotless, lubricated and torqued properly, or it will be (very expensive) tears before bedtime!

    Calvin covers it in his latest corner:

    http://www.parktool.com/repair/calvinscorner.asp

    I could be cruel and suggest that if you need to use a compact you may be wiser getting an R700 and spending the difference on a weekend away, but I wouldn't dream of doing that!
  • maddog 2
    maddog 2 Posts: 8,114
    ta rob

    those Park pics give me a better idea how it fits together

    I currently run a R700 but I've been on the lookout for something a bit, well, cooler for a while. Not that I've got £300+ to blow, as that's clearly madness, but one may come up s./hand, you never know. I'll have another look at the Campag stuff I think...
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • robbarker
    robbarker Posts: 1,367
    maddog 2 wrote:
    I'll have another look at the Campag stuff I think...

    I wouldn't touch one personally. The engineering is awful as far as I can see. There is no adjustment to allow for variation in BB shell width, hence the "wavy washer" bodge, and the bolt that holds the thing together has habit of coming apart with use.

    I'd try and pick up an Ultegra SL or FSA if you want flash, but both will show the wear far more quickly than your R700.

    FWIW I sold mine and replaced it with an Ultegra 53/39 ;-)
  • maddog 2
    maddog 2 Posts: 8,114
    yeah I just read the same about the UT stuff. Sounds a bit iffy for sure.

    I fitted a Ultegra SL compact to a mate's bike the other day actually, which was nice. But I'm not so sure it's a big enough jump up from the R700 to be worth it really. It looks a bit better but the engineering was very similar.

    Shimano should just produce the R700 with the finish of the grey 2007/8 DA stuff. That would be ideal. But then maybe that is the Ultegra SL.... 8)
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer

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