scottwitting

Run time obviously depends on type of riding, as a guide I can get my 22kg son on his 16 two thirds of the way round the Sherwood red mountain bike trail before a battery change is required. This is about 5 miles. My understanding of C rating is that you multiply the capacity (8Ah say) by the C rating (15's about the lowest) to give a current that the battery is comfortable being used at. So this gives 120 amps. Given that the Oset 16 is fitted with a 40 amp fuse I reason that the current rating of the battery is never going to be a limiting factor! These batteries are designed to be used in a quadcopter type thing that will drain the battery in minutes, not half an hour like on an Oset. No BMS, just train the child to tell you when a light's gone. I'm not aware of a plug and play BMS that is suitable. Parallel charge. After a ride (down to two lights ~ 37v) I storage charge the batteries if they're not going to be used for a while and then fully charge (balance charge every time) a day or two before riding. I'm no expert but this seems to work and keeps my battery's quite well balanced. Hope this helps, sorry for the delay replying.

I have run two 36V Osets on Lipos for while now, a 16 and a 20 lite. I use two 5s 8000mAh batteries in series, so 10 cells, 37V nominal. The throttle lights drop from three to two lights at a convenient 37V so you, or the child, know to change batteries then. Bike operates fine with these.

If you don't fancy the LiPo route then invest in some new lead batteries. If your existing batteries are relatively old they'll have gradually reduced in capacity over time, new batteries should give a noticeable increase in performance. Best value way is not to buy batteries from Oset but to search eBay for the right size/voltage/capacity batteries as these will be significantly cheaper.

We've been round Sherwood mountain bike trails a few times with no bother. Also ride in local parks and woodland with no issue. Even riden past a policeman on a woodland footpath - he was more interested in the bikes than telling us off! As others have said, remain responsible and you should get very little bother. At the risk of diverting the thread, the place we've had most objection to the boy's riding has been trials! Don't get me wrong, I fully appreciate the club's potential insurance implications for letting non entered riders ride and how relations with landowners can be damaged if an incident occurs, but it's also in a club's interest to promote the sport to the riders of tomorrow! Fortunately more and more clubs have a conducted route now but kids are riding from as young as two and can't compete until they are four!

Not blaming the bike already are you?

Most people doing serious trials with a 20 upgrade to the 'competition rear wheel set' - £159 through Oset (http://osetbikes.com/gb/parts/wheel-sets/ also through Trials UK but a bit dearer - http://www.trialsuk.co.uk/products/oset-rear-competition-trials-wheel) This comes as standard on the 20 Racing and gives you a 3" wide rear tyre (same as TY80 rear tyre I believe). Think it comes with a security bolt so you can run at 2psi or less for best grip. Don't think you can simply buy the wider tyre and fit to the standard rim, although I haven't personally tried!

After having my thermostat fail during a trial, nearly boiling my bike and not being able to finish, I now carry a small link wire (6mm male spade each end if I remember right) that can now be quickly used to link out the thermostat and make the fan run all the time. I also run the bike up to temp and watch for the fan cutting in after each wash off and carb clean.

We have an 'old type' 2011 12.5. This has been a great bike for both our boys to learn on. It's biggest weakness, in my opinion, is it's sharpness, it is quite aggressive and doesn't have any throttle response adjustment (just top speed). This hasn't been a major issue though. You can get a tidy one like this for £400 to £500 if you keep an eye on eBay. The other slight issue was the chain constantly coming off. This has been improved since I put new chain and sprockets on, but I still feel the chain was a little to small gauge for the bike. Oh, the plastic chain guard soon gets smashed too. I think (not 100% sure about chain size on Eco) these three issues have been rectified on the 2015 12.5's which are pretty much a complete re-design. If I was buying one now I'd probably go for the Eco, think most of the upgrades on the racing just add a bit more bling. In my opinion there is no need for disk brakes if you keep the V and band brakes well maintained. The band brake is very good, neat & tidy, effective and low maintenance. I wouldn't hesitate to buy a used one, they're fairly simple to maintain and repair if needed and hold their value quite well. Have fun!

Great! Thanks for that, found those on a map so should give her a few to go at. How about the Sunday? Any idea where we'll be heading?

I think I squashed the batteries on the side so that may have been it. I have a Hobby King X120 charger, it's the touch screen type that gives quite a lot of info whilst charging. I balanced charged each battery individually at 6 amps (so less than 1C). I do balance charge my other batteries but thought with this being the first charge I'd do them one at once. The bike is fitted with a 40 amp fuse so obviously won't pull anywhere near the 10C the batteries are rated too. Yes, I'm now removing batteries from the bike when not being used and storing in fire safe bags in a safer place (how much are lipo batteries effected by cold? Could you store them outside during winter nights, or would this do damage?). I charge in a sealed metal box in a 'safe'ish corner of the garage with a smoke alarm mounted above. 'Never leave unattended whilst charging' - is this practical? Does this just mean be in the house, or stay in the garage!!

I thought I'd share a recent near miss I had with some lipo batteries whilst attempting to convert our little lads 12.5 from lead to lipo....... After running a 36v (pairs of 5s batteries in series) 16" bike on lipo for a while with no problems I decided to get some for the young un's 12.5. Went for some of these http://www.hobbyking.com/hobbyking/store/__56843__Multistar_High_Capacity_6S_8000mAh_Multi_Rotor_Lipo_Pack.html which, after careful measuring, seemed like they would fit nicely. Once they arrived I taped them together, wrapped them in some 8mm foam and duct taped them up. Trying them in the bikes battery tray they were a good fit, just dropping in under their own weight. I put them on charge whilst I got to work soldiering up a harness. One charged fine but the other never seemed to want to finish, one cell would not go above 4.18v. In the end I stopped the charge myself. Next I attached the parallel lead and went to fit them in the bike again. This time they were a tighter fit, as if the batteries (or one) had swollen a bit. I was just easing them in when there was quite a loud and#39;pop' and smoke started to be emitted. My first reaction was to step away but then I realized what might be happening so grabbed the bike, wheeled it outside and ripped out the batteries. Within less than 30 seconds there were three foot high flames coming from the packs, which after several more minutes burnt out leaving a smoldering pile of ash, see pic below. I'm still not certain what caused this, the batteries weren't punctured or impacted in any way. The force I was applying to the batteries at the time was probably similar to a small child standing on them, not excessive in my view. I'm quite certain the battery that and#39;popped' was the one that failed to charge properly. I'm progressing this with Hobby King to see what they say and hopefully get a refund. Looking back I feel extremely lucky not to have destroyed the bike or the entire garage. The foam base in the battery tray melted and there was a bit of smoke dust on bits of the bike, but no real damage. I'm going to be much more careful in future how I store and charge these batteries! They are great when working ok, but can obviously go badly wrong!

Hope I got in then!? Sent entry quite early so if it's first come, first served I might be ok! Will the route or section group locations be available anywhere in advance? My wife and boys (2 and 4) will be hoping to watch if there are some easily accessible groups. She likes to know where she's heading before hand.

Good job our girls are doing a top job of representing GB then!

I've had a sit on one that young Dominic Horne rides. Apart from suspension settings (I'm 6ft 3, 14 stone, compared to his 4 stone ish!) it felt like I could have comfortably ridden it in sections. Dom rides it well, seen it zip up quite a steep climb (which my old boy on a TYZ struggled with - technique...). And apparently it will be fitted with a more powerful motor than the prototype has. It all looks proper too, neat finish & components. Think this will bridge the gap for youngsters to full size bikes. Will they ever have to use a clutch?!

Hi gwhy, thanks for the reply. Impressive device! Sounds ideal, with it having variable throttle maps and power/speed settings would it replace parts on the Oset (controller?) or could it just plug in-line and perform the soft cut off function? How much do you sell them for if you don't mind me asking? I've been looking at some speed controllers on HK (like this http://www.hobbyking.com/hobbyking/store/__29665__Turnigy_dlux_80A_HV_Brushless_Speed_Controller_OPTO_UK_Warehouse_.html) . Some seem to feature a programmable soft cut off function, but also do more than I require. They also have three output wires (for connection to a brushless motor) so I'm not sure how that would work with just the two wires on the Oset? They also have an input from a receiver which I guess sets the speed. I'm unsure what this would need to be fed with to see a permanent 'throttle fully open' signal, if that makes sense.