I have already moaned about the ridiculous low BB on my 29 er Trance but it is really getting to me to the point of considering swapping frames to something with a sensible BB height. It will have to be a 29er though so I can use all the bits I bought for this build. Before I get to this stage what else can I do to reduce the effect of the low BB?
I have bought thin pedals, tall tyres and am wondering whether to get a shorter armed crankset, XT come in 165 mm length but this is going to give a strange pedalling action, surely?Would going to 140/150mm forks make a significant difference? This is at least cheaper than a new frame!
Failing all this what frame will give me a reasonable BB height?

170mm cranks help a little and you wont even notice the difference, I have a specialised fsr that has a low bb, its a pain sometimes but very comfortable and handles really well otherwise.

I had this on an old Spesh Enduro. I fitted a slightly longer shock with the same travel. That sorted it out perfectly.

An alternative is offset bushes.

The frame design will dictate how effective this is (it’ll usually steepen the head angle)

Is it a PF30 frame? http://www.universalcycles.com/shopping/product_details.php?id=41682

longer forks?

I think learning to love it has to be tried and will take time

Try starting some threads on how stable it is at speed due to the very low BB

More seriously

More pressure in rear shock (just setthe air for 100mm of travel and raide the BB 20mm ?) or more compression damping

Taller tyres would make a diffrence

How long have you had it? Could just take time to get used to it.

My Transition Bandit has a low BB height, initially I was getting a lot of pedal strikes. After a few months I adapted my technique and rarely get any now.

I´m riding the new Orbea Rallon which has a very low BB, and it´s fantastic. They spec it with 170mm cranks and I have put thin Raceface Atlas pedals on and it rides so well, you get all the stability in corners which makes it great but now I rarely have pedal strikes. The Orbea uses a BOS shock which stays quite high in its travel and I run it quite hard, meaning less SAG, all of which helps a lot.

I´m sure you could look at running less sag on the trance, I normally run less sag on my short travel 29ér (an Orbea Occam 29), because I think that the wheels cope with the small stuff and a stiffer shock helps for bigger bumps and jumps.

How high is the BB? Both those Orbea´s are pretty low as well.

Sounds like you’ve half made your mind up regarding new frame ..
Taller tyres could help as could shorter cranks and thinner pedals – but all these upgrades could cost more than swapping out frame if you got a good sale on current frame and then got a good deal on second hand frame with lower bb

I have an El-Guapo, a frame that has a reputation for a low BB.

When I first got it I used to notice pedal strikes a reasonable amount but I got used to it. Also fitted 170mm cranks and run about 25% sag.

Also remind yourself just how damn good it feels at speed.

http://www.powercranks.com/cld.html

http://www.cervelo.com/en/engineering/ask-the-engineers/crank-length.html

http://mountainbikingzane.files.wordpress.com/2009/09/cranklength-1.pdf

Some real food for thought there. Like most people I thought going for shorter cranks would be a handicap but it seems that won’t be the case from the evidence above. That does seem a starting point as you can get a 170mm Deore crankset for under £50.

Just started on the crank length reading. Interesting stuff. About 18 months ago I mashed an ankle and it must loads of movement that made cycling to difficult to bother with. It’s now seems Ok with me riding pain free about 4 hours a week.

But it ingesting to see that I can probably get away with less movement if necessary by using shorter cranks

What problem is the low BB causing? Can’t you just adjust technique?’

I’m relieved that I’m not alone in hating the recent trend for low BBs. Hopefully it won’t be too long till the fad fades and the cycle moves back to higher BBs that you can actually cycle up good techy hills.
At which point I’ll buy me a new bike.

I’m the opposite. Gagging for a lower bb. 13-13.5″ has been great on bikes in the past, I’ve even had more confidence on rocky stuff on my old hardtail with an 11″ bb!

Currently thinking about a 120 travel 29er frame with 650 wheels along with a slightly longer fork (160) that will raise it up at the bb (after dropping approx 38mm at the bb with the change in wheels/tyres).
Even with the raise at the front,because it’s a steep head tube/seat tube short travel bike,the angles will end up less relaxed than the likes of an Intense Carbine.. but with shorter travel out back. Putting all that guff aside, the bb will be probably end up about 20-24mm lower.

I love to wangle stuff together that shouldn’t work. My fav hardtail was a 140 26 trail hardtail with a 120mm 29er fork and it rode better than what it came with (loved the fork kicked out front a tad more too)

Having ridden Laggan black with the bike that has an 11″ bb, pedal strikes are the least of my worries compared to something so confidence shattering as a bike with a high bb.

As for the crank length links above,I reckon with all the stuff you read about 140 through to 180 crank lengths,with no noticeable power differences, I think the bit to understand is the hip angle along with the knee angle at the part of the stroke where you begin to put the power down. With a 180mm arm length ridden with the saddle at the correct height,the amount the hip and knee is flexed at the top of the stroke is so much compared to the 140 crank that your leg can in no way put out the same power as it can at the top of the stroke when using the 140 crank length.

Like sitting on a very low chair, it’s very hard to lift the body weight at the beginning of the effort compared to the point where we’re not that far off from standing up.

By comparison with hard tails which had gone before, I struggled when I first had my 26″ wheel Trance.

BB was lower with no sag anyway and felt impossibly low even at 20% sag! which was how I initially ran the shock, simply to overcome the “problem” .

A relatively short time later, realising that more, (30%) sag, really made the bike work better, I discovered that in the meantime, I really had adapted my riding style , almost subconsciously. By that I mean, not pedalling when I didn’t have to. Better pedal positioning , downhill over techy stuff and generally using the bike more efficiently.

Sure, I still get the odd strike, but then did on older bikes too, now and then.

I ride an Intense 275 in the summer and when it’s rolling freely you really appreciate the low BB. But in recent years we’ve trended toward riding slow-tech that needs precise pedalling to maintain flow, and the low BB is a bloody nuisance.

I’m taken by the shorter crank articles, Canfield Brothers do them down to 155mm, just need to lower the gearing to suit.

I appreciate to some extent you can use technique to avoid pedal strikes but pedalling uphill on a rutty or rocky surface means it is difficult to avoid whacking pedals down. What really shocked me on my first ride was dragging the pedals in corners on the road! Now I know , I have learnt to avoid this but it is something I never had to think about on my old 26″ FS or current HT.
Still some interesting suggestions to try, thanks chaps.

Had this issue with my old Stumpy. Changed to 165mm cranks in the end and noticed a considerable reduction in strikes but no real change in how I was pedalling – then again, I don’t pay much attention to cadence on the mtb. Oddly, post-ride leg ache reduced too which I put down to a more ‘natural’ feeling action.

Having ridden Laggan black with the bike that has an 11″ bb, pedal strikes are the least of my worries.

That’ll be because Laggan has almost no interesting uphill sections. It’s just dull fireroad on the uphills.

Which is a shame as it’s awesome apart from that.

No, I was meaning the rocky step stuff. I forgot about all the stuff on the way up! Must’ve been about 4 years since I was there.

I found the bottom bracket a little low on my Giant Anthem at first, compared to previous bikes. Love I now though – stick with, you’ll adapt.