[Closed] XC race bike head angle

It's an XC bike, surely you want it weighted over the front on twisty bits?

dragon - Member
It's an XC bike, surely you want it weighted over the front on twisty bits?

As above. If anything when I read the first half of your post I was thinking 80mm stem.

Have you tried the 70mm flipped the other way? (I'm thinking you mean you have it flipped down atm)

It's an XC bike, surely you want it weighted over the front on twisty bits?

No, too much weight over the front makes it hard to change direction quickly because the front tyre is working hard. You and the bike pivot around the contact patch of the rear wheel, so the closer your centre of mass is to that point the faster your bike can change direction. It's why they bend seat tubes to tuck the rear wheel under on some bikes.

You only want weight over the front to keep the tyre gripping in long fast corners. Short sharp slow ones you want your weight back.

If I flip the stem to a positive rise, I'm sitting too upright on climbs.

Try another 70mm stem with less rise?

Point is I don't want the bars higher.

What's the angle of the stem you've got -/+?
Any spacers you can put on top off the stem rather then under?

Does it feel like the bike wants to tuck in the twisty descents?

Slackening the head angle would pull some weight off the front wheel, but it'll reduce the reach also, so if the frame is a little too small it may make you feel more cramped. It'll be a minor difference, but it will be shorter.

What's the offset on the fork? A shorter offset may help by increasing trail. Which would help with tuck, if that's the problem.

I guess the other question is, how often do you ride your XC bike? And do you ride a long and slack bike most of the time?

Yes it's tucking under.

What's the offset on the fork?

Aaaaahh.. yeah this might be the issue.. It's a Trek innit and has G2 geometry so they come with forks with different offset don't they? Is it more or less I can't remember. I only have normal Rebas.

Bugger. Haven't the cash for new forks.

so they come with forks with different offset don't they?

Usually 51mm iirc.

So it seems they have MORE offset to create less trail. Hmm. The only thing I can change is the head angle isn't it? But it would have to be steeper to reduce the trail. That might help with the reach but could cause other issue with the handling.

Might as well get an angleset, see what I can do. £50 at superstar.

51mm offset is pretty much standard for 29ers, so it's probably not that.

My money's on the frame just being too short, but a slackset would probably help if you're determined to keep it.

£50

Put it toward a new correctly sized frame/bike with a 68.5 HA.

I'm selling a large Boardman Pro 29er triple butted alu HT frame with a 68.5 HA, if you wanna take Kryton's superb advice.

😉

FFS, the whole point of spending small amounts of money to fix things is because I haven't got large amounts of money for new frames.

You may all be swimming in cash, but not everyone is.

You cant polish a turd... Etc

Just put all of those little bits of money away. It all adds up.

Thanks for that wisdom. I had no idea lots of small amounts of money added up into a large amount.

So in the intervening five years, I should just put up with it. Thanks for that contribution, that really gives me insight into trail, head angle and tucking under.

You can't polish a turd, but this isn't a turd it's a bike, and bikes can be adjusted and tweaked. Hence the thread.

Offset bushings are cheaper

Sorry molgrips, i appreciate my quip isnt helpful in the way you want ot to be. But i have been down the wrong sized frame route and now i have the right size / geo the feel is amazingly different. Im merely suggesting if its wrong, itll always be wrong no matter waht you add to it. Probably.

As discussd, perhaps try an offset headset or rear shock bushings. If the back is short or to move your weight backward what about a layback seat post? Or it could be technique - drop your heels, lean back and take the weight off the front when cornering?

Offset shock bushings.. interesting, hadn't thought of that. Seatpost is already laid back and saddle rearwards.

Leaning back is already part of the deal but with the saddle where it is, there's not a lot of scope. A dropper would probably help, but in some ways I don't want to be pressing buttons all the time on every up and down.

I can just put up with it, but it's a shame to have to slow down on corners. I suspect that getting a 51mm offset fork might help but that's not easy to do on the cheap.

Leave the 90mm stem on for a month.

I reckon it's more down to your position on the bike while riding said twisty trails, try (although you may already be doing so) getting you're backside lower and realxing the grip a tad, and lean you not the bike so the grippy bit of the tyre is doing the work and the whole thing is more upright and therefore stable. Might work, might chuck you into a tree 😆

The saddle prevents me from getting my backside lower. I'm normally pretty good at these kinds of trails, this bike definitely makes me feel less secure doing these things. And the fact it was designed around a different fork offset suggests it's not working optimally.

I think what you are describing is potentially a Trek 29er trait. I have a Trek 29er with G2 and it isn't great in slow twisty stuff, you just have to man handle them through as best as you can. But on fast stuff they are freaking awesome. I bloody love mine, and like all bikes, cars etc. setup is about balancing different requirements, and personally I can put up with average through slow twisty stuff, for blooming fast everywhere else.

My question is how have you potentially ended up with too small a frame with the wrong fork offset? Mind even with the wrong offset it shouldn't be horrific.

It's not horrific, really. Just a bit of a tendency, which annoys me somewhat. And you are right about balance. I can improve it by raising the stem, but then it feels less good putting power down. I can also get used to it and learn to work with it. Balance is one of the things I appreciate in a bike though, and it's a little frustrating. Although to be honest, this particular piece of trail might be highlighting this trait - I could take it further afield.

I bought the frame as an excellent bargain s/h from here, it seemed big enough but it's rather difficult to tell when it's not built. There's no size sticker on it. And the fork was one I already had that seemed suitable.

I could simply save up and wait for a new fork to present itself s/h, but the Slackerizer idea intrigues but so do the fork bushings. Geometry feels a bit better with more sag in the shock but then it is too soft, so that might address it.

Built up a Superfly recently, geometry optimised for 51mm offset. Thought about spending money I didnt have on new forks too, but decided to just lump the old Fox 32s on and it rides fine. I might opt for 51mm offset SIDs or reba sometime in the future, but only because the white fox forks look terrible on a black frame with black wheels and black decals, and I only have crown lockout which I keep forgetting about mid race.

Its an XC race 29er. Its made for going real fast up climbs and on flat straights, you are over thinking it on technical descent stuff. Adapt to ride the stuff on a less forgiving bike and accept it just won't feel as capable as a more trail bike kind of set up.

you are over thinking it on technical descent stuff

I whole heartedly disagree. XC racing involves going fast down and along as well as up. XC race courses aren't usually that steep (but sometimes) but twisty single track features heavily. Also, my previous XC race bike flew on the climbs and was also extremely quick on the singletrack.

Well I raised the stem by 10mm but kept it flipped. Felt too high at first, but actually got used to it quite quickly and it made all the difference. Much better. Raised the saddle about 5mm and it was better for power too. And the bar width felt much better too.

Moral of the story - even 10mm makes a difference, so make sure you've thought about your bike and tweaked it before you change it for something else, you bike tarts 🙂

Now just need to decide if I want wiggly bars or not.

Recently put an angleset on a canyon xc hardtail. Head angle reduced by around 1.5 degrees. Feels good so far.

If you feel that the geometry feels better with the shock soft but it's mushy, then offset bushings would definitely work, clearances permuting. I have an older 100mm fs with too high a bottom bracket so I put one bushing in and the improvement cornering and descending is massive, I'm thinking of going for a second offset bushing to lower / slacken even more.

It's a really cheap fix and easy to swap out if you don't like it, you'd get to run the shock firmer but with more hunkered down geometry, one bushing only costs between 10 and 20 quid, depending on supplier. My bike is too short for me as well and this mod has bought it back to life, Sitting lower in the bike gives a feeling of the bike being longer in my experience and I'm certainly riding it a lot more.

Hmmm. By coincidence my Anthem needs a new shock bushing. At 70 degrees I guess I could get 69 easily?

Link to a good shop?

@inkster that's for that, good to know. Cheaper fix than the angle set. Will try it out at some point.

There is no bushing on the lower eyelet of an anthem (shares lower link pivot) so you can only fit one.You'll get half a degree if you're lucky (less if it's an 8mm shock bolt).

Indeed,I was just reading up on it.

If I have to replace the bush anyway I may as well give it a go though, £12 is a cheap way to lose even 1/2 a degree.

Had similar issues with my old bike, this over the front feeling is not at all pleasant. Fannied around with stems/ bars/ forks/ spacers for ages until I admitted what I knew in the first place, that the frame was just too small. Try having a shot on a similar larger bike if you can.

You cant polish a turd... Etc

Right, well Kryton57 was dead wrong.

Got hold of some 51mm offset forks. They are better than the Rebas as forks (Fox F32), slightly shorter A2C too. But the bike is completely different in corners. Really solid, stable and planted, I can feel the front hooking up really well. And it's really nippy in the twisty bits.

Also fitted a slightly wider riser bar which has helped the riding position - I may cut that back down again.

So to all of you who're ready to write the bike off with 'oh it's only an XC bike they always handle shite' - not true. This one's brilliant now it's set up properly.

Well, I’m pleased to have been found wrong. Glad its worked out for you.

Nice one.

Congratulations , you must be one of the elite few who can notice the difference that changing fork offset by 5mm makes .

Anyone prepared to leave the bike over would have noticed. Huge difference. Nothing to do with being elite, just need to lean it over.

My solution was going to be bar ends. So that you could have less reach in the twists but a stretch up hill

Glad you are sorted. It's good to be reminded that it is worth persevering with setup

Also fitted a slightly wider riser bar which has helped the riding position - I may cut that back down again.

Why think about cutting them down if they help the riding position .

Congratulations , you must be one of the elite few who can notice the difference that changing fork offset by 5mm makes

It has the same effect on trail as just under 1 degree on the head angle and people obsess about that enough for anglesets to exist.

But moving from 46mm offset to 51 mm offset should have exactly the opposite effect to what he is claiming it to have .