Fork travel on hardtails – how much is too much?

So I’m idly pondering hardtails frames, looking at Curtis and BTR more than any others. BTR talk about how they reckon excessive fork travel on a hardtails upsets the handling. I’ve got 140mm on my 650b hardtail and never noticed anything untoward. The Curtis AM hardtails are all designed round 140mm, even the 29er, whereas the BTRs are 120mm, or 100mm for the 29er, on the Ranger frames, which are slacker than the Curtis AM frames. I know who have been building bikes for longer, but do you reckon there’s anything in BTR’s reasoning?

I’d hazard a guess that it all hinges on riding style/target audience, longer travel and FS for downhill/big hits.

Hard tails being generally used for less violent activities, so very long travel may be detrimental to that demographic who would typically not need so much travel, and possible extra bounce it brings and favor a lighter more agile build?

What they said IMHO hardtails are used more for mincing along stuff* than for full on DH so less travel is generally required

I found my 456 to be a front end light going up hill with 140 and use TALAS if i had to pick i would have gone for 120 mm personally

* i have 100 mm 26 er and yes i could ride the lakes and proper mountains on it but honestly I would be using my FS for such a task

YMMV

160mm on my production shan, wouldn’t want any less.

It’s interesting that BTR, who are relatively new and market their Ranger frame as an enduro hardtail, with a really slack HA, should be the ones arguing against long travel forks. The concept of the long travel hardtail is pretty well established too.

Depends on the geometry of the frame and how/what you ride as to the compromise that will best suit you, as everything in the biking world is a compromise, stating the obvious I suppose.

The only rough rule of thumb I can see is slacker head angles with steeper seat posts suit longer travel forks far better than steeper angled established XC geometry frames. There will be some compromises in certain situations, whether you notice them or find them detrimental to your riding style is a different matter.

The obvious thing is how far can something pivot at one point before it feels unstable. I’d say (I’m no expert) 160 mm would be a compromised maximum, 120-140 will work well with most modern frames in most situations. When you get to 140 and above, slacker geo frames with HA’s about 66.5-67.5 really help IME.

Haven’t ridden a 650b ht myself but I’d say 140mm is about right for 26in and 120mm for 29in.

Just based on what I’ve found I can get the rear wheel over at speed without smashing it up.

I’ve got 140 on my 29er hardtail and it feels fine.

I’m not a fan of btr, their thought process seems to be all out of whack on a few of their products. ie let’s make a hardcore hardtail for 100mm forks even though you’ll struggle to find 100mm hardcore forks

The geometry and quality of travel more important in my opinion.
My riding skillz are also more important than 20mm of travel.
120mm on 26er Sanderson.

Got to be all down to geometry and frame design. Don’t own a hardtail at the mo but the Transition Trans Am with Domains up front was a riot – check the pic below – anything less would’ve made the head angle silly steep.

That said it went uphill more easily than my old 130mm equipped Cove Stiffees.

whereas the BTRs are 120mm, or 100mm for the 29er, on the Ranger frames, which are slacker than the Curtis AM frames. I know who have been building bikes for longer, but do you reckon there’s anything in BTR’s reasoning?

‘m not a fan of btr, their thought process seems to be all out of whack on a few of their products. ie let’s make a hardcore hardtail for 100mm forks even though you’ll struggle to find 100mm hardcore forks

Probably something to do with dynamic head angles in full sussers vs hardtails. Less travel on a hardtail = more stable angles.

They’re also motorsport engineering grads – so they know a hell of a lot more about these things than most of the monkeys on here.

Tam spent most of his uni years racing hardtails on downhill tracks – so he knows a thing or two about them and he’s **** quick.

Pikes come in a 100mm flavor btw.

I’m a graduate zoo keeper, I know a hell of a lot more about monkeys than you.

What do you make of those rear post mounts Tom? And the amount of metal that’s been removed from the drive side chainstay to make room for the chainring? I’m not an engineer so I’ve no legitimate idea beyond frowning and wondering ‘is that really strong enough…?’

Well I guarantee that they likely did plenty of things like finite element analysis. Tam always struck me as a person who knew his stuff. Never saw or heard of any of their protos breaking either. They were hard on bikes as well.

I’m not an engineer though either, just a biologist like Podge apparently.

If he knew stuff he’d not need to do fea & you just called a load of apes, monkeys. That’s proper basic stuff so I’m calling you out on being a biologist too.

BTR Ranger – The ‘Butch’ Review

As I suspected, short travel fork to aid chassis stability.

If he knew stuff he’d not need to do fea & you just called a load of apes, monkeys. That’s proper basic stuff so I’m calling you out on being a biologist too.

I wouldn’t demean apes by associating them with STW.

If he knew stuff he’d not need to do fea

Apparently, Airbus, Boeing, Lockheed etc don’t know their stuff. Well **** me, I’m never flying again.

Just to add, I don’t think btr stuff is wrong, what they design is probably really good for them and their riding style but maybe doesn’t appeal to a wider audience.

Like anything podge.

I’d get battered half to death by the Ranger with a 100mm fork. Would like one for the laughs but I have other things to buy really.

160mm on my production shan, wouldn’t want any less.

Same on mine. set of Lyrics, was ace and totally suited the bike

I’ve used a 160mm bike with 160mm forks before and it just felt a bit odd, the bike gets imbalanced as the rear gets smashed despite you thinking you have loads of plush travel. In future if i got another i think I’d go for a 140.

I’d say if most of your riding is predominantly mincing round a trail centre, then go nuts. Longer is better. 160mm preferably.

THis thread might be of interest.

http://singletrackworld.com/forum/topic/short-travel-hardtails

BTR clearly know what they’re talking about. I think I remember the guy who started it from the SDH forum days, and like me, he can clearly ride a bike 😉

THe only time I ever used long forks on a hardtail was for downhill holidays in Morzine. Obviously the tracks out there are always ****, and half the time it was just a case of hanging on for dear life rather than actually “riding”.

Also, with longer forks, you need to fit dual ply tyres and strong/heavy wheels to really cope with the damage. Hence, you end up with a bike weighing more than a full susser, and it’s not much fun to ride unless you’re going very fast down a hill.

Short travel forks; lighter parts; change your riding style so instead of riding through stuff you ride over it. That’s what hardtails are all about imo.

I’m having fun on a 140mm 32.5lbs 29er hardtail riding natural trails at mince to medium speeds. Who do I have to answer to for doing it all wrong?

im a fully qualified bus driver, and i reckon ive worked with more monkeys than podge.

I have 140 on my 26″p7. perfect for me. Don’t know about other wheel sizes.
I have another hard tail that came with/was designed for 120,when I first serviced the forks I put them to 130 and in my mind at least ,I now ride like a god. Which is not quite as well as Mr Taylforth 😉

I’m having fun

It sounds like you’re doing it all right!

Which is not quite as well as Mr Taylforth

I imagine you ride better than I do; I no longer bother 😀

Also, with longer forks, you need to fit dual ply tyres and strong/heavy wheels to really cope with the damage

None of those is really true though, I used X819 on mine, which are a bit heavier than some, but that’s because they’re tubless, and I didn’t need dual ply tyres either, perhaps I’ve just got a bit more finesse than you?

😉

I found my 456 to be a front end light going up hill with 140 and use TALAS if i had to pick i would have gone for 120 mm personally

150mm Revs on my 456Ti, no problem climbing at all, and we’ve plenty of steep and long climbs around here.

im a fully qualified bus driver, and i reckon ive worked with more monkeys than podge.

I’m a policeman, so congratulations on coming second 🙂

150mm on my c456. With modern forks with proper damping, i can’t see a problem tbh!

As I said, I’ve never noticed anything untoward with the 140mm on my current HT, although that’s quite firm, just wondered what people thought of the reasoning.

Depends on the hardtail- give it forks as long as it wants. Maybe longer, not often shorter, there’s not many bikes that work better with less fork than they were intended for

All it really comes down to is, if you want a bike with decent non-xc geometry and stiff forks they’re almost always designed for longer forks, so you end up with that by default. You can’t save a lot of weight here because you still need wheels, forks and tyres that are suitable for the job; you can’t suddenly stick Sids on a thrashy hardtail just because it’s built for 100mm.

Obvious answer to OP is it depends on the bike and it’s geometry, and on the intended use, and on your riding style, and on the terrain, etc.

My BFe was a bit wandery at 150 but is just about right at 130. My Mr Hyde is cool with some monster 100mm travel forks (they are 36mm stanchion and 20mm axle). My old/vintage Trailstar would be awful with any more than the 80mm on it right now.

Of course with the ones I keep looking at you can have custom sizing and geometry, so it’s not quite as easy as ‘fit what it’s designed for’.

150mm 650b Revs on my 26″ Transam.
Light front on steep climbs but I love it.

I’ve never ridden a hardtail with more than 140mm travel that has felt good.

100-130mm is the sweet spot IMO. Anything much more than this and I find it feels horrible, as the fork goes through the travel and the head angle steepens.

This may help.

‘DOES THAT TAKE 160MM FORKS?’ ‘IS THAT 160MM TRAVEL?’ ‘CAN I FIT 160MM FORKS?’ THESE ARE QUESTIONS THAT WE HEAR/READ AT BTR ALMOST DAILY, AND YOU KNOW WHAT? NO; NO IT DOESN’T/NO IT ISN’T/NO YOU CAN’T.
Let me expand. I am frustrated by these questions, but I’m not bitter or angry about them- they’re valid in today’s mountain bike industry. Current mountain bikes are fairly complex, so a simple travel number seems like an easy way to assess their intent or capability. Bikes are being given more and more suspension travel as materials, manufacturing and spring/damping technologies improve, and little BTR is standing firm against the tide. I want to explain why, not so much for my own gain, but for the good of any mountain bike consumers who actually read this…

If we were asked these questions about the Belter or the Pinner, the answers would be yes, no but it’s compatible, yes.

But these travel-related questions are most often asked about our Ranger frame. Other bikes aimed at ‘enduro’ riding are most often given ~160mm travel nowadays, so we get asked if the Ranger fits in the same mold. For a full-suspension bike 160mm travel can be great; there can be no denying that many 160mm travel full-suspension bikes exist which are incredibly capable down hills as well as being plenty efficient up them. Brilliant! Several hardtail ‘enduro’ frames exist which can accept 160mm forks; some are even designed around this value, but all are a compromise.

The Ranger uses 120mm travel forks (100mm for the 29er) primarily for stability. Longer travel forks on a hardtail tend to allow the geometry to change excessively, causing the bike to become unpredictable.

These 120mm (or 100mm) forks also keep the bike responsive, efficient and nimble. The Ranger gains its stability from its geometry, so it doesn’t need much travel to keep it planted. Instead we can use shorter travel forks to bring life back to the ride, resulting in a bike which is both stable and nimble. Nope, that’s not a contradiction of terms!

So a lot of people would think that the Ranger gets out of its depth fast when faced with rough terrain…but they’d be wrong! You just need to set up the forks the right way. In order to deal with aggressive riding, ‘short travel’ forks need to be more progressive than their 160mm travel brothers. This is generally as simple as installing a couple of extra ‘bottomless tokens’ in your Pike, or adding some suspension fluid to the positive air chamber on forks without a transfer port, or changing to a firmer spring on a coil fork. Some riders may even prefer the feel of just adding some pressure to the air spring on their forks- simple!

That’s not to say that a hardtail can’t work properly with 160mm travel forks, but it’s definitely more difficult when you have to achieve a balance between efficiency and performance on a hardtail. Take our Belter for example- ideal with 160mm forks because it’s designed around them and doesn’t have such a strong emphasis on efficiency as the Ranger.

So what happens if you put 160mm forks on a Ranger? Well it probably won’t break, but we’re not going to guarantee that. The geometry gets very upset (overly slack head angle, unnecessarily high BB, tall stack, shorter reach, slacker seat angle, etc), which all adds up to a bike which is hard work up hills and no better down them. It’s not rubbish, it’s just worse than it could be and that sucks.

The Ranger is best with 120mm (100mm for the 29er) forks. Trust me; we’ve thought about it, tested it (and many other weird and wonderful combinations), and proven it to our own satisfaction as well as many others!

That’s what prompted the question 🙂

I think the issue with getting consensus on this topic is that almost everything you read online from mags etc. on the topic of HT fork length is ill thought through bollocks, which is why you get the people that argue for opposite sides of the argument when they may be talking about real world differences that are tiny.

Personally I think the key to getting the right travel on your HT bike is:

1. Be honest with yourself about where and what you’ll ride. Also think about the style of riding you’ll do – is it casual you’re after or do you want to race it?

2. Buy the best forks you can. Avoid coil forks and 32mm chassis for 150mm travel HT bikes. You also either want a tuneable air spring or adjustable HSC. If you cant do either of these on your choice of air fork, walk away.

3. Pick a frame that is the way you want it for the travel you want. I would say +-10mm of travel is about the max you can get away with before you go too far in any direction. So if you like the geo at 120mm, don’t then stick 150s on it. Its not the same bike. Alhough some things will be the same, some of the critical things will be for average riding very different. Too many compromises IMHO.

i know ..
it makes no sense..
its unpredictable..
just wrong…

but its a lot of fun !
and perfect for me… 😀

prince albert prototype with 44mm headtube and 150mm marzocchi FR forks