Reba / Bottomless tokens / Bike misuse :-)

larkim

Son is looking at whether investing in some bottomless tokens would be a good idea for his 120mm rebas fitted to a Canyon Nerve.

Budget constraints meant he couldn't purchase something more in the Enduro category as a bike at the time, but being a 16 year old he doesn't spend his time pedalling furiously over 45 miles of cross country single track. He likes to hit jumps at trail centres etc.

This means he sometimes bottoms out his forks, and therefore has added more air than his weight / sag would normally dictate.

For someone in that situation would adding bottomless tokens be a good or a bad thing? Obviously "buy a new fork" or "buy a new bike which is more suited to the riding you do" are two solid answers, but ££££ is not "bottomless" so for the moment he's got what he's got.

The Rookie

Bottomless would be the way to go, it will keep small bump sensitivity while ramping up the spring assist faster.

Also worth him learning his damper and getting a 'XC' setting and a 'jump' setting in his mind as that will also help hold the front end up.

Amazon was the cheapest place for the tokens when I last looked.

larkim

Cheers, that's really helpful.

(Linked to my other post about the negative chamber, I didn't add that when I came to depressurise his forks he had his rebas set at 220 thinking "more air will solve the problem". Given he weighs 65kg, and the forks themselves say don't exceed 200, I think we had a near miss there...)

larkim

btw Rookie - care to expand on that damper / setting bit? AIUI he only has air and rebound settings to play around with on the Rebas, the damper isn't adjustable whilst out and about is it? Keen to learn as usual!

EDIT: just realised that damping is adjustable of course, via the lockout ring which is analogue not binary.

JGTR

Had similar issues with my Rebas, with correct sag the fork would bottom out too easy. I did some research and it is a relatively common issue and possibly a trait of Rebas. The way I dealt with it was to ignore sag and set the pressure so that on a ride I would use all the travel without bottoming out - takes a bit of experimenting. Only downside was that it left the fork a bit stiff and lacking small bump compliance so I stripped and rebuilt the fork using low friction seals from TF tuned and fitted one bottomless token (£30 from eBay USA). It is better but still lacks a bit of small bump compliance compared to other forks I've ridden. I still don't use sag and have settled on a pressure that allows full travel for my weight without bottoming out.

rockmonkeysc

You're going to need a new bike soon. The Nerve won't take a lot of that abuse and the forks are just plain wrong for it. Adding bottomless tokens won't really make them suitable for jumping, you need a decent damper to control the dive, they're still not going to work on big hits. The bikes geometry is just wrong as well, minor mistakes are going to result in big crashes on higher speed, bigger jumps.
Sell the bike and get a much more suitable freeride bike instead of an xc bike.

larkim

Helpful as ever RMSC

He knows / I know this is a compromise bike. But money isn't unlimited and the bike serves many purposes. For the time being, that's there kit that is available. I'll report back when it all cracks and he decapitates himself on a big crash.

kickaxe

larkim wrote:

Helpful as ever RMSC

He knows / I know this is a compromise bike. But money isn't unlimited and the bike serves many purposes. For the time being, that's there kit that is available. I'll report back when it all cracks and he decapitates himself on a big crash.

To be honest, if the Nerve is in good shape, you can sell it for quite a bit of money, let him add some of his allowance and you could put a bit in the pot too, and you have the money for a nice, discounted trail/enduro bike. Obviously this doesn't work for everyone always, and I don't know your situation, but after doing the same last fall (I'm still around your sons age), I was able to get a giant Trance relatively easily, without my family or me being rich. Might be worth a thought and/or a discussion with the rest of the family.

rockmonkeysc

It'd a lot cheaper to sell the bike now than wait for it to break.
I see it all the time down the local trails. Parents buy their kids an xc bike which they then ride in an unsympathetic way, mainly jumping and they're quickly broken. I've seen snapped chain stays, cracked fork crowns, pringled wheels, snapped fork steerers and some pretty nasty injuries form crashes which just wouldn't have happened on a mice slack freeride or downhill or enduro bike.

The Rookie

Most Reba's have a compression damper on the top of the right hand fork leg, which specific Reba has he got?

Agree with RMSC though he would be better off on an old second had more suitable bike.

larkim

It's a 2015 120mm Reba RL.

In all seriousness, I do understand the points made about a bike being fit for purpose. It would be boring if I posted here saying "I've bought a really good cross country bike, can you tell me if its OK to use it for cross country." The reality is that all bikes end up being used in a compromised way, unless you really have no financial issues. Whilst this bike does get used on trail centre jump areas, it does also get used equally for pedaling on local single track, round trail centre red and black routes, on the road up to his work, for local commutes etc. No one area of bike use gets particularly more than others, so the bike still remains a solid choice. He's not hitting 30 foot road gaps or planning to take part in Megavalanche, and if he did he'd need more specific kit. But for the time being, we've got what we've got. If he was riding a Trance or an Anthem I doubt anyone would bat an eyelid...

The Rookie

The RL has an adjustable damper - Blue knob on the top of the right stanchion - not sure why you think he has no compression damper setting?
https://www.sram.com/rockshox/products/reba-rl

Trance no, Anthem yes people would be raising an eyebrow.

cooldad

I agree with larkim. It's unlikely to explode into tiny pieces and kill him.

One of our guys rides a Nerve. He's not small and hammers it down some pretty rough stuff fairly rapidly. It's not exactly a racy XC type bike. It's a trail bike and will handle most things a trail centre will throw at it.

larkim

Rookie - I was being dense, I'd forgotten that what is a lockout knob on my bike is a compression damper adjustment on the Rebas (I think I edited my earlier post to clarify that).

Back on topic - tokens fitted now. Should the pressure be the same as pre-tokens, or different (as a starter for 10)?

The Rookie

The pressure needs to be slightly lower as the pressure when sagged will be the same (as its the same area holding up the same weight).

larkim

Cheers, that's what I thought. Time to start experimenting with numbers of tokens and pressures. Max is 4 for the Reba, stuck 3 in for the first attempt.

rockmonkeysc

It's not going to solve your problem. Filling the air spring with spacers will just cause a really harsh ramp up instead of bottoming. It's a bit of a bodge where you really need a decent damper.

larkim

There isn't really a problem to be solved, just a tuning of what we've got on hand. The whole air pressure thing has got tied up in the issues we had with the negative chamber being over-pressurised, so he's back to learning about using the forks with full travel and correct pressures. Its about getting the best out of what we've got for limited outlays. Tokens may (or may not) make an improvement that he likes. For £15, its worth a shot.

cooldad

I'm guessing RM doesn't have kids, or he'd know that in addition to bikes, we need to give them stuff like food, clothes and school, which costs a bit.

He did have a girlfriend once, but she disappeared after he paid her.

rockmonkeysc

I do have two kids and I pay for both of their horses plus lessons and equipment.
I'd rather see them have the right equipment than have unsuitable kit which could potentially be dangerous if misused (you ever seen a fork crown snap?)
It will cost you very little, if anything to sell the xc bike and buy something which won't fail spectacularly and dangerously with the riding your son is doing.

larkim

You're overplaying it. This isn't some £99 bso from toys r us. It's a decent low end trail bike with adequate if unspectacular equipment. I get that you don't like the bike (you reckon it has a flexible frame i seem to recall). But suggesting that a Reba tapered fork is likely to snap it's crown on moderate jumps at a trail centre is just nuts. He's not at BPW or hurtling down Fort William. Yes, I'm sure he could overcook it but he knows the bikes limits too.

If you want to stop people riding Reba forks at Llandegla, start a campaign. But don't expect much success

rockmonkeysc

Rebas aren't strong enough for proper jumps. Tapered or no. I've seen Revelations crack through the lower arch from just one badly landed jump.
It's not just a case of breaking the bike, when the fork dives on a landing, the head angle gets very steep. That means very little room for errors before it all goes horribly wrong.
Little jumps a few foot high should be fine but anything bigger and things WILL break.
I'm not a big fan of Canyon bikes but any short travel trail / xc bike would have the same problems with jumping.

larkim

You'll just have to trust me when I say we're not overcooking this. But no one can say we haven't been warned!

poah

RockmonkeySC wrote:

Rebas aren't strong enough for proper jumps.

just as well he said "He likes to hit jumps at trail centres" so no DH bike park type jumps here.

rockmonkeysc

Trail centre jumps seem to be getting up to a decent size now. 40 foot gaps at Bike Park Wales, twenty foot at Afan if you double up some of the rollers, 50 foot tables at Tidworth, twenty foot doubles at FoD.
Trail centres are at last starting to get more interesting.

poah

RockmonkeySC wrote:

Trail centre jumps seem to be getting up to a decent size now. 40 foot gaps at Bike Park Wales, twenty foot at Afan if you double up some of the rollers, 50 foot tables at Tidworth, twenty foot doubles at FoD.
Trail centres are at last starting to get more interesting.

BPW is a DH uplift centre, its not like that at llandegla unless I missed it

rockmonkeysc

Llandegla has the most tame black trail I've ever ridden!
Bike Park Wales is definitely not downhill. There's one trail there worth riding on a downhill bike, everything else is much better suited to trail bikes. One of the black trails even has half a mile of very flat trail to get to the start and a short climb in the middle.

larkim

If 40 foot gaps and 50 foot tables is what you thought I meant by jumps, RMSC, then I can see why you think the current bike isn't up to it.

Instead we're talking the skills area at Llandegla, the freeride track there (probably the biggest jumps) and the "tame" black trail. Whilst that might still be at the sharper end of what the bike and the fork are designed for, I think you can rest a little easier about his safety.

rockmonkeysc

I wouldn't do those bigger freeride jumps on an xc bike. Get those wrong and there's a good chance of breaking something. I'd do them on an enduro bike but not an xc bike.
Stuff like the skills loop will be fine though.

cooldad

It's sold as a trail bike, not an XC, FWIW.

But there are too many categories. Enduro is one of those stupid ones.

rockmonkeysc

Enduro is just a new name for what used to be all mountain.
I'd say the Canyon is more xc than trail. My Transition is more what I'd say is a trail bike, along with bikes like Giant Trance, Specialized Stumpjumper etc.