Project GRUBB (1960 F.H.Grubb, holdsworth era plain 531)

[randomdan]

Re:

Thanks guys,

The chain doesn't sit too badly on the chainring, although there is some wear, but I've seen much worse on MTB chainrings that have worked just fine with a new chain. The tension from the deraliur is really not very much at all and it's a rather puny looking spring so I don't want to overstretch it, but I might have to push my luck a few clicks more with it.

It might also be my bad habit of backpedaling when coasting, as this slacks out the top section of the chain making it leap off at the chainring end. I think if I had a double chainring and a front derailier it wouldn't happen.

I've also just putting the gearing into sheldon's gear calculator to get some perspective:
The Grubb has a 48t chainring, largest gear on the back is 24t with 27" wheel and 165mm crank = 4.2 ratio
my SS Orange P7 has 38t chainring, 16t freewheel with 26" wheel and 175mm crank = 4.5 ratio.

I can get up all of the local hills I regularly ride on the P7, and the Grubb has an easier ratio plus less tyre resistance... so should be fine. I just need to man up

 

[Muddy paw]

That's not to bad a gearing tbh as i was thinking that seems the same setup as i had on my old holdsworth which had a single 48 tooth chainset with a low gear freewheel setup of 23 teeth and here's the Suntour model freewheel i was running , https://www.google.co.uk/url?sa=i&rct=j ... 7364937511

and i got up some surprisingly steep climbs on my old bike and i say surprising because it was a 1970s 19" sports bike which weren't as big as mtb's and it was a hi tensile steel frame so it wasn't very light weight either ..

Right then your chain doesn't seem to bad for a nice fit and the wear n tare seems admirable on your chain wheel and i'm not certain if this would help but i'd try taking a couple of links out of the chain and see if that helps to keep the chain seated better ..