FatAndSlow

I recently bought an old bike with a Suntour Sprint groupset. It's got a 13-19 freewheel, and as a fairly unfit guy who's used to mountain bikes, pushing a 42-19 up a steep hill (of which there are a lot where I live) is beyond daunting. I'm just wondering how big I can go in terms of freewheel cogs with the sprint rear mech.
Any info greatly appreciated.
P.S. does anyone know anything about Ammaco road bikes in the late 80s? From what I gather they were makers of cheap and nasty stuff by the mid-90s, but this bike I bought seems very nicely made from Columbus tubing with quality components.

leecycle

I'm using a 13-24T freewheel with my SunTour Sprint RD without any problems; IIRC the official max is 26T.

rtruectoc

i have a nos cyclone 7000 rd. i got it because the max is 28 teeth. just one step below sprint. you could also put a 39 tooth chainring on, i happen to have one of those as well. pm me. i switched over to shimano. i have to say for friction the suntour stuff is much snappier though

rtruectoc

if you go to sheldon browns gear calculator , you can see that the 39/28 combo will give you like a 36 inch low gear. thats almost like having a compact crank with a 25 in the back

MalcolmsFrejus

Sprint 9000 was reccomended to go to max 23 for index and 26 in friction.
At least according to Frank Berto's Complete Guide to Upgrading Your Bike.
Chain wrap capacity = 26.
I have a Sprint (pre-index version) and it has trouble getting up on a 25.
The Cyclone is/was rated to 26 max cog and 30 capacity.

FatAndSlow

Thanks for your replies everyone! That gives me some guidance - something like a 39-23 ratio sounds much more manageable.