Got a Frog 69 MTB - a really good bike. Gets used weekly and the determination shown on the climbs suggests that it won' be long before I'll be shouting for a break to catch my breath.
However, the climbs are a bit of a struggle...the chainset is 140mm cranks and a 32t ring. It has a chainguard but I've not worked out how to replace the ring - it looks like it is a one-piece solution.
So I'm needing to find square taper 140mm cranks that can take a 30t narrow-wide ring. Narrow-wide as the mech doesn't have a clutch and I suspect the chain will bounce a fair amount.
I'm off to start trying to get Google to give me a solution, but has anyone else changed the chainset/ring on a kids bike and if so, what did you use?
Thanks.
Think SJS cycles do some Thorn ones that go down to that size.
+1 for sjs. We have thorn cranks with 30t chainrings.
Could you go bigger on the back?
I've put a 11-40 sun race 8 speed cassette on my son's frog 52. I bought a road link for the rear mech but didn't need it in the end.
I use Suntour xct jnr cranks on my kids bikes. They’re only available in 152mm tho.
I binned the middle (heavy steel) ring and use a 30t n/w. The cranks are actually pretty light.
Vpace out of Germany, or spawn.
I put trailcraft cranks on my lads bike. They have 140 and 152
Ideal, thanks for the pointers. The Tailcoat look nice, I found them after posting, but initial thought is a bit pricey as I may need a wider bottom bracket as well. (however, if everything similar is the same price then not pricey) Will check Thorn and SJS out, thanks.
Kids Racing is where you should be heading, these are what you want.
They go down to 135mm, have a narrow Q factor and are 104bcd so you can fit down to a 28t with spacers.
Ideal, thanks.
I didn't find any of the options much good, in the end I just went SLX 1x11 with a 46T rear. My daughter's bike has a triple up front - she can just about manage front shifting, but she's 7.
I got severe earache when I suggested adding a double at the front...so I'll do this and she can improve on the climbs without realising I've been tweaking the gearing.
Heard back from Frog, the chainset is a 1-piece unit so can't replace ring.
So either new chainset with a 30t ring or maybe a wider range cassette.
Alivio SGS rear mech, 9spd cassette is currently 12-36, so looks to maybe need a SunRace 11-40 (but unsure if I'd need an adapter for the mech).
New cassette is cheaper and easier to swap over (unless an adapter is needed for mech then it adds a bit of time).
