What's an "MRP chain guide"?



!Jones <[email protected]> wrote:
>
> See:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=130140481277&...
>
> There's a "chain guide" being sold with the crank... I guess "MRP" is
> a brand? So, what does it do?
>
> (It guides the chain, Bozo!)
>
> Yeah, but why? What's it for?


MRP is (or was) a manufacturer that made parts for retaining the chain
on single-ring derailleur bikes. These were specifically intended for
downhill MTB racing.

The MRP chain "guide" consisted of a pair of thin plate rings that
bolted on outboard of the singlke toothed chainring, along with a
boomerang-shaped gizmo that mounted by being pinched between the BB
cup and the BB shell. The ends of the boomerang carried two small
rubber sheaves. The chain ran around the chainring and inside the
grooved sheaves which were mounted close to the chainring's side
plates, making it almost impossible for the chain to jump off the
chainring.
 
On Wed, 08 Aug 2007 14:15:10 -0000, in rec.bicycles.tech Chalo
<[email protected]> wrote:

>!Jones <[email protected]> wrote:
>>
>> See:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&rd=1&item=130140481277&...
>>
>> There's a "chain guide" being sold with the crank... I guess "MRP" is
>> a brand? So, what does it do?
>>
>> (It guides the chain, Bozo!)
>>
>> Yeah, but why? What's it for?

>
>Here's a picture of a bike sporting an MRP guide. It should be worth
>a thousand words in explaining the rationale for such a thing:
>
>http://www.pinkbike.com/photo/1435505/
>
>Chalo
>


Thanks