For adult mountain bikes, its the norm for the bike to come supplied with a suspension fork. At the cheap BSO end of the market these are often basic coil sprung forks with little or no damping. Should you wish to upgrade there are many forks the rider can choose from. However, for kids bikes (24) there is very little in the way of choice if you want a decent fork. There are 4 current air forks that are available that you could consider. These are 1 1/8 steerer size
SR suntour make the XCR-lo air 24 with 63mm travel which has an adjustable air spring, fixed rebound with both disc and cantilever brake bosses. It has 28mm magnesium stanchions, alloy crown and weights in at 1863g. No idea where to purchase these forks but I’m assuming any SR suntour dealer can order them in
Spinner make the Grind air 24 with 65mm of travel. it has 25.4mm stanchions, alloy steerer and crown, V/disc or disc only brake mounts,air spring with lock out but no rebound. It also has the option of a remote lock out. The spinner grind air 24 weights in at 1725g. S pinner forks can be purchased from Spinner Europe lukasz.nowak@bluepill.pl
RST supple the final 2 fork, the F1RST air 24 and the arial 24 . the Arial 24 has 3 options ML, TNL and RL. The all have an air spring, 60mm of travel, alloy steerer and crown, magnesium lowers, steel stations. The ML has a mechanical lockout, the RL and TNL has hydraulic lock out with the RL being a remote. The weights are as follows RL 2.01kg, TNL 1.93 and the ML 1.73kg
The F1RST air comes in two flavours with the only difference being a remote lock out. The specs are 60mm travel, alloy steerer crown and stanchions (28.6mm), magnesium lowers, disc and V-brake mounts, compression and rebound adjust with air spring. The remote lock version weights 1.65kg while the standard version is 1.6kg.
Its the RST F1RST air 24 forks that I purchased for Lewis’s Christmas. I got them from bike-discount.de and they make a significant improvement in that they actually work.
MTB mumblings 
Useful post. I wondered if you had any experience of fitting the RST to an Islabike Beinn 24? 8 year old getting into red routes now but we can’t afford Islabikes’ Creig range at £750! Islabike reckon adding suspension forks changes the handling of their Beinn 24 for the worse, but I reckon they are missing a trick as there is nothing in-between their £350 and £750 range MTBs.
Hi Mark,
The axle to crown measurement for the RST first 24’s is 400mm. Thats from just under the headset to the middle of the axle. So long as the rigid fork is around that length (no more than 20mm difference) then you should be fine. I’ve set the sag at 15% for Lewis so the actual A2C is a bit less.
The RST forks look to be about 70mm longer than the standard Beinn forks… Reckon this is too much of a difference?
I would say so
I’m thinking of upgrading my daughters Frog 62 (v.similar to the Beinn 24) with the RST 24″ Air forks. I’ve measured the A2C on the Frog’s rigid forks and they’re 365mm (approx), so we’re 35mm adrift based on your measurement of 400mm (btw, when looking at 24″ bikes with RST forks the gap from top of tyre to crown looks a lot more than 35mm if comparing them to the Frog)
Anyway, I’m not too worried as it’ll raise the front end a bit and I think the Frog and Isla put the kids into too much of a forward-lean position, so this will help, but I’m am trying to figure out how much this will affect the head angle which seem pretty slack anyway.
Any ideas or knowledge on that ?
1 degree for every 20mm
Cheers. A crude estimate of the head angle on the Frog is 70-69.5 (I took a level photo using a tripod and used angle measuring software/tools, took the average of 1/2 dozen attempts to line it up). So, at 20mm per 1 deg, that would be approx 1.75 degrees or 68.25….. seems acceptable. Only one way to find out.
Thanks
I have just purchased a pair of XCR-lo air 24s for my sons Saracen. The rest of the bike is fine but the wheels are heavy and the forks are mince!
http://www.xxcycle.com/fork-suspension-sr-suntour-sf12-xcr-lo-24-air-24-black,,en.php
might try them out on my daughters Beinn 24 and get him to see if they effect the handling.
Also wanting to fit these to a beinn 24. Anyone done this ? Tks
I’ve seen them on a beinn 24 at comrie croft. selling mine for £110 posted if you are interested
All – For a few ££ J Tech Suspension lowered a set of RST First 24’s from 60mm to 40mm travel to help me reduce the axle to crown height (and match front to rear travel on a custom Scott Spark 20 Jr build – build report is on singletrackworld.)
What is the fork rake (or trail) on that RST fork? Thanks
not a clue jeff sorry
Providing an update that the SR Suntour XCR Air 24 fork was updated for 2016 with more linear and usable travel. The older XCR Air 24 fork had a negative strong with an overly high spring rate so the fork was unable to fully extend with any more than 75 psi of pressure in the air chamber. The new version works much better with the 45 psi necessary for my son.I found this review of the new XCR Air 24 fork: http://www.dirtmerchantbikes.com/kids-bikes/sr-suntour-xcr-air-lo-suspension-fork-for-24-wheels