Am doing a bike build with my son – just turned 9, tall for his age and around 35kg. It’s going on a 27.5 Brand x frame.

Now, go easy here, because I’m still learning but I want to do this to make him a bit more hands on and he is keen too, but I’m learning as I go too (not done so much on bikes myself, but cars, general diy etc).

So overall requirement is 27.5 fork, 120mm travel, light (I think 2kg is around the max). Something that actually will work at a low weight too – and from what I have read that means I’m thinking an air fork that I’m going to need to change the oils to better tune it. And happy to go 2nd hand as there are budget considerations (trying to keep it under £100 and pref lower the better) and do a diy service at the same if going to change oils.

Probably best to stop there for advice as to whether I’m on the right track or not…. If I am ….

Other considerations are I have some 9mmQR 26 inch wheels that I’m going to start him on so would be great to not have to change that to a 15×100 front. I suppose I would like it to be on his bike for a little while as hoping to get a good few years out of this bike, but in around 3-4 years, I could throw it on the younger’s future bike build and he can upgrade etc. Kind of things I have seen and thought about are Suntour Raidons, Rockshox TK air models….

Really appreciate both general advice and guidance as well as suggestions for the right kind of fork etc.

In an ideal world you’d get a coil fork as they are plusher and would give you better small hit sensitivity, but getting springs for low weights isn’t very easy.
I’d get the best air rock shox with aluminium stantions you can find. Before brexit you could find bargains in Europe. Reba would be good if you can get one.

In an ideal world you’d get a coil fork as they are plusher and would give you better small hit sensitivity, but getting springs for low weights isn’t very easy.

Thanks Akira and you raise an important question over coils that I have been mulling. I have considered this as I’ve seen some cheap 2nd hand rockshox 30 medium coil forks (I guess because people upgrading to air) and thought about getting an x soft coil, but I’m not sure if he’s still just too light for it? Or are there other aftermarket coils that would work at his weight?

Make sure it’s not a Fox fork. Your child will be too light for the fork to work properly. My wife was told by the fox service Center she was too light. I can’t remember the exact details but it was to do with getting full travel and the damping circuits unless you went completely custom.  Rockshox work at a lower weight was the advice we received

I think the main issue will be the damper side. At 58kg I struggle with forks feeling too harsh; Charger damper 1, and Charger 2 both wide open are just about OK for me but not perfect.

At 35kg you will need to use a very light oil, or even modify the damper to allow more oil flow.

Get an old open bath fork. I reccomend something like an early recon, or revelation – with a moco damper, and ideally a dual air spring.

Change the oil for something half the weight. Set the air spring up well.

What more do you want?

Personally, I’d just get a rigid carbon fork for a 9yo; it’ll only get left out all hours in the rain when he/she rides it to school, and they’re light enough that they don’t need the support.

Make sure it’s not a Fox fork

Thanks for that tip, that works for me because they are generally v expensive, but I’ll stop looking around for those.

I think the main issue will be the damper side. At 58kg I struggle with forks feeling too harsh; Charger damper 1, and Charger 2 both wide open are just about OK for me but not perfect.

At 35kg you will need to use a very light oil, or even modify the damper to allow more oil flow.

I remember reading on some old threads (that I can’t find any more) about using light weight oils on an air fork for kids. Might be something with a bit of trial and error. Also, over the next few years he’ll hopefully grow into it a bit more (goodness knows he eats me out of house and home, still skinny as a rake though)!

I managed to modify an old Moco damper by re drilling the holes at the bottom to increase oil flow. I ran that with Reverb oil in the damper which is lighter.

Get an old open bath fork. I reccomend something like an early recon, or revelation – with a moco damper, and ideally a dual air spring.

OK, lots for me to think about here, open bath forks… off to research what that means or how early a fork are we talking….

The other option I have here is to get an older 26 inch fork with more like a 140mm, and then a 27.5 fork when I move him over to a bigger wheels. That might give me another year and he’ll be a bit heavier. But I don’t know it will make that much difference…. Main benefit is that I don’t have to sort out new wheels now and then can get a whatever front axle wheel to suit the appropriate fork.

Open bath for RS meant “motion control” or MoCo. Also see MOCO DNA, Moco Blackbox, e.t.c. I.e. a load of shims attached to a top cap and a load of oil it sits in. Change the oil weight, change the damping.

Old means pre 2018 probably. Nothing that says charger (this is a closed bladder damper).

Open bath for RS meant “motion control” or MoCo. Also see MOCO DNA, Moco Blackbox, e.t.c. I.e. a load of shims attached to a top cap and a load of oil it sits in. Change the oil weight, change the damping.

Old means pre 2018 probably. Nothing that says charger (this is a closed bladder damper).

Thanks, the terminology was confusing me a bit!

continuity

Would a rockshox 30 Gold RL be a reasonable call then as it as MoCo (I think). Over my price bracket, but new for £150 ish.

I’d probably err towards a secondhand revelation or recon that you can service yourself and uses standard 32mm stanchions etc personally. If you’re going to take it apart to change the oil then at least you can properly service it. The 30 range are all built to a real budget and are heavy as lead.

Thank you again continuity.

And any thoughts on a sektor or pike that has a larger travel, but adjusting it down with tokens (as I have read that reducing volume with tokens can help sensitivity)?

Having come up that way with our two girls and trying every permutation out there we ended up with dual air Revelations on their bikes, Coils couldn’t get a light enough spring to get full travel even after TF tuned had worked on them. You can get spacers to reduce the travel if needed. The later forks need an air shaft swap to reduce travel
We never had to mess with the oil on the Revelations just fine tuned with the air. They ran 150mm ones on the FS and 130mm on the hard tails

That Giant looks amazing!

Forget coils at that weight. I ran the lightest coil spring available in forks (Manitou & Marzocchi) when I was twice their weight.

Maybe I need to reconsider the budget, probably be cheaper in the long run and quite time saving!

Looking at a couple of second hand revelations, what’s the difference between

FS-RVL-RC3-A3
And
FS-RVL-RCT3-A3??

I’d seriously consider a rigid fork and a big (plus) tyre, the grip and bump absorption on a big tyre suits a kid better, have seen it work really well, my own kid had an air fork which never really helped him.

I’d seriously consider a rigid fork and a big (plus) tyre, the grip and bump absorption on a big tyre suits a kid better, have seen it work really well, my own kid had an air fork which never really helped him.

This is not something I’ve thought about. What kind of fork do you get and how big is a big tyre, does that mean new wheels, or can you also a big tyre on the current wheel. And is our just the front that gets a big tyre? Sorry of Noddy questions!

At some point he is going to ask you for some suspension forks so it’s probably more cost effective to bite the bullet now, have a look on Pinkbike as you can drill down to search for stuff

Giant was when she was 10 years old in Verbier, moved up from a Stinky JR.
She is now 23 and has had a few bikes since then, far better rider than I will ever be.

Yes a sektor would be fine as long as it doesn’t have TK damping. It’s just a cheap revelation with a heavier CSU.

Anything rc3 or rct3 tend to be three position adjustable low-speed compression (on, platform, lock) with some form of blowoff adjustment. I wouldn’t bother.

Thanks all for the input, I think I’m going to bit the bullet and get a 27.5 revaltion and spend double the budget – ouch. And now I need a new 26 15*100 front wheel, doh!

mrbigglesworth

I’d seriously consider a rigid fork and a big (plus) tyre, the grip and bump absorption on a big tyre suits a kid better, have seen it work really well, my own kid had an air fork which never really helped him.

This is not something I’ve thought about. What kind of fork do you get and how big is a big tyre, does that mean new wheels, or can you also a big tyre on the current wheel. And is our just the front that gets a big tyre? Sorry of Noddy questions!

The bike the kid had was a 24″ wheeeled commencal with 2.6 tyres – he progressed amazingly well on it, enough bounce with the tyres but did’t have the weight of a fork.

https://www.commencal-store.co.uk/ramones-24-black-white-2021-c2x31636857

26″ wheel with a big tyre in a rigid fork would work well for an older kid.

My 9 year old has a Ripcord and the forks that came as standard. They are RockShox Judy Silver TK 26 and appear to work really well and have a decent rebound adjust. I cant remember what pre load pressure we put in there but it was a tiny amount (just used SRAM’s fork set up guide to get started with the mind to fettle from there), so little in fact that I was sceptical it would be ok yet they work well.

Make sure it’s not a Fox fork

Nonsense.
My boys at 7 and up were lapping whistler bike park on a new old stock 2013 fox f120 32 with a ctd damper with standard tune. Picked up off eBay for ~100quid for a 24″ ripcord.
At 8 they moved onto a f120 32 with fit4 damper and Evol airshaft.
Cheaper tear off fox 32s might be around with the budget grip1 damper which would actually be the better damper for a sparrow weight rider anyway.

However, a decent condition fox is often hard to find for bargain basement money and you might have more success with rockshox for this. Thankfully you’re not needing a strait steerer fork.
Anyhow. Used Rockshox serviced with 2.5w oil and that’ll be good, but avoid the low end and coil sprung stuff.
Or Manitou are the current darlings for kids forks but there won’t be any used ones with kid specific tunes about yet.

i have just been through this and managed to pick up a pair of 2017 RS Reba RL’s in 100m travel, 27.5 wheelsize, qr with non-tapered steering… got for about £180 on the bay.

have just bought a 120mm air-shaft and will swap over this week.

very light, very plush and can easily be tuned for a very light (ie kid) rider. my little one is happily getting through his travel on the jump track and you can see the fork working well in normal riding (whereas most cheapy forks seem to very little).

i admit i got lucky in finding the fork, but they are out there.