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[Closed] Following on from the slack HA debate... Who finds low BB heights a revelation?

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Recently transferring back to my Commencal supernormal HT, following a cracked headtube rebuild 🙄 , I suddenly realised what had originally made it such a confidence-inspiring ride.

I may end up clipping the pedals here, there and everywhere now, but compared to the Giant Anthem I'd been using in its place for a few months, the low(er) BB hight means you sit 'in' rather than 'on' the bike.

Despite the lack of rear suspension, I find it better on low speed tech stuff and higher speed drops. It even seems to climb technical stuff better too.. although I can't work that out (lower centre of gravity maybe?).


 
Posted : 16/12/2010 10:20 am
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+1

Sticking long forks on bikes slackens the headtube angle and gives you more suspension which can make a bike feel better in certain conditions, but it also raises the bottom bracket, which takes away some of the benefits (IMHO). It also reduces the seat angle which is another -ve in my opinion, especially for technical climbing.

Having recently ridden my Whyte 19 against a Cotic Soda I instantly felt the benefit of the lower bb on the Cotic (I felt the difference and measured after). Although that was not the only difference between the two it was one I felt had a big influence - you ride on the Whyte and in the Cotic, as you said above.

Downside as you mention is increased pedal strike - which up to a point I would be happy to live with. For smoother trails the lower bottom bracket is an outrite win as it carves better (skiing terminology - but I'm people sure will understand what I mean and not hang me for it 😉 ). For really rocky rooty terrain I can see how a higher bottom bracket will have it's benefits - although it will make the bike more nervous (as it does on my Whyte).


 
Posted : 16/12/2010 11:01 am
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I prefer a low BB too. Might be something to do with my Roadrunner technique on tricky bits though... 🙂

From the balance point of view a higher one is supposed to have some advantages. Cleland bikes promote higher BBs.


 
Posted : 16/12/2010 11:04 am
 fbk
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For the reasons stated above, I actually prefer a slightly higher BB on my XC bike - means I can keep pedaling through stuff & round corners without fear of clunking the pedal.

On my DH bike however, the low BB does inspire a bit more confidence (lower CoG etc).


 
Posted : 16/12/2010 11:26 am
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its better for railling the corners, but im not sure its beneficial for square edged hits.


 
Posted : 16/12/2010 11:30 am
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don't forget about us tall chaps...

i like a low BB cos it means my saddle is lower also.

my saddle is approximately 17ft above my handlebars, and i don't want those any higher thanks.

my old enduro had a 275mm BB height (compressed), i had a few pedal-strikes, but i quickly learned to pedal strategically if it got rocky.

The BB on my Blue pig is too high, imho etc.

(edit; i've thought about this for a minute, and i'm bound to find [i]anything[/i] 'high' after i got used to the enduro)


 
Posted : 16/12/2010 11:40 am
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No problems with high BBs here. I like to have the clearance.


 
Posted : 16/12/2010 11:43 am
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Low BB is a must as far as I'm concerned, otherwise I might as well be on a penny farthing.


 
Posted : 16/12/2010 12:29 pm
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I wouldn't say I want a low BB. I just don't want a stupid high one 😯

20mm higher is noticeable 🙄


 
Posted : 16/12/2010 12:50 pm
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i prefer the almost permanent advantage of a low bb to the occasional disadvantage of pedal strikes / timing my pedalling. there are places when a higher bb's better though, slower and techier places generally.

it's one of a 29ers biggest advantages - the bb drop is greater than a 26 even if the actual height is the same.


 
Posted : 16/12/2010 1:21 pm
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I love high BBs, I find ground clearence very useful, the extra inch makes much more difference in that respect that it does to a lower centre of gravity.


 
Posted : 16/12/2010 1:54 pm
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low bb on my (old model) trance
even with 140mm fork and 165 cranks I get pedal strikes and get nearly thrown off maybe once every 2hr (mostly in narrow sandy ruts with heather at sides)
it's a bloody great bike though, esp for the price

(I can pedal my bullit forever without the same issues - it's a surprisingly nice ride too, 7 inches travel xc, with lightish wheels 😳 )


 
Posted : 16/12/2010 2:10 pm
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Depends where you're riding.

In the Peaks a high BB is a mild advantage as there's very few corners to rail(dude), but there's an awful lot of rock steps to climb up.

Pure DH stuff, or twisty swoopy singletrack, they're great though.

I can change the BB height on my Uzzi by faffing with the dropouts, and it does make a huge difference to how hard you can sling the bike into corners.


 
Posted : 16/12/2010 2:38 pm
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You think it's high on an Anthem?? WHat else have you ridden to compare that to as it's lower than many, unless of course you're refering to the Anthem X & not the Anthem?


 
Posted : 16/12/2010 2:40 pm
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I got to the point where I started avoiding a number of our local trails as they were MX trails and severely rutted. the ST4 with a decent sag and a low BB was a nightmare. Looking forward to trying them again on the SS scandal to see if there's a difference but they were certainly easier to ride on my old Malt 2 HT.

Don't get me wrong. When out on rocky descents and man made trails it's awesome to have a low BB and slack head tube but for this variety of riding, which our local group seems to like, it was a REAL pain.


 
Posted : 16/12/2010 3:00 pm
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Having had a couple of bikes with low BBs, I could comment on this, but as I'm always wrong I don't think I'll bother. 🙄


 
Posted : 16/12/2010 3:29 pm
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lol @ PP. Go on you might as well, today is another day 🙂


 
Posted : 16/12/2010 3:44 pm
 duir
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My Mythic Spitfire has a very low for a 5" bike BB and sits around 13". That makes it tricky on technical climbs and pedal strikes are common. However when descending the low BB is incredible especially in corners and makes it ride like the advert says "the downhillers XC bike".

It comes with a second shock position that raises the BB and steepens the HA but whilst easier to pedal uphill it makes it boring downhill.


 
Posted : 16/12/2010 4:42 pm
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I could comment on this, but as I'm always wrong I don't think I'll bother.

...handbags 😉

I only tease. 🙂

Anthem is with my uniquely 'twangy', hardtailesque and possibly-not-quite-enough-suspension-sag setup and the BB is probably 15mm higher than my Commie, which is approx. 30mm BB height, both measured static.

Dunno whether either of them are relatively 'low' or 'high', or what.. One bike just feels riden 'in', the other 'on'.

Interestingly, it's riding regularly in the Peak that has brought me to this conclusion. I can handle the pedal strikes, no problem, but the extra technical confidence of a low BB rocks! Quite literally..


 
Posted : 16/12/2010 7:11 pm
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I'm in the low BB camp, I've owned both extremes and hated my high BB bike so much. The low BB bike was a joy to play on 90% of the time, it had it's issues in ruts and between rocks, but you learn to time your pedal strokes or just accept the odd bash..
Currently, I'm building up a Cube Stereo frame with a 13" BB (150mm fork), but with 160mm forks which, with my tape measure, raises the BB to a still very low 13.25".
I like play biking and I suspect, and certainly in my case, really low BBs are a bit of a skillz compensator.


 
Posted : 17/12/2010 12:49 am
 GW
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I've never liked high BBs, for me hardtails become horrible above a 12.5" BB height and BB height is far more important to me on a bike than head angle.
FS depends on travel, my current two have 12.6 and 13.6 BB heights (4.5" and 8" travel DH bikes)

congratulations Ahwhiles - I wondered how long it would be before someone chimed in with their utterly pointless sagged bb height measurement 🙄 my money was on Brant (You snooze you lose, eh?) 😉


 
Posted : 17/12/2010 1:18 am
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Low (long and slack) please!

If you're finding clearance issues just hit stuff faster and skim it. Which incidentally a low bb will help with.

Climbing through ruts and rocks can be more of a pain with the low rider it's true, but I'd rather have the odd strike and feel more of a hero overall.


 
Posted : 17/12/2010 3:11 am
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Being an avid fashion follower my bikes have got lower and slacker over the last 6 yrs and i have yet to find a disadvantage.

Any pedal strikes are a good trade off for the confidence these things give.

With good technique there isn't much you can't still climb and everywhere else is more fun.

B.N.Nana (my bro in law) went from ride [u]everything[/u] to not even riding his bike once he treat himself to that 'boutique' Ellsworth Moment...

Bring on the Cube, i want my riding buddy back. :mrgreen:


 
Posted : 17/12/2010 6:44 am
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I used to have a pair of Madison clear glasses years ago which I used in the winter. As soon as I put them on I immediately felt the bike was another 2 inches higher and riding it was horrible. Things that were just normal became scary. Obviously it had no effect on the handling of the bike it was just a change in perception caused I assume by distortion in the lens but I soon stopped using them.


 
Posted : 17/12/2010 9:29 am

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