29er fork rake and geometry.
Al, ridden twice in anger. First time mostly flatish/rockyish tracks, which l was surprised how comfortable it was for a rigid bike. Second ride last night was regular off road route done on fs or ht. It was enjoyable in places,but sometimes just didnt feel right, although again considering it’s rigid, some of the more demanding downhill sections were ok. Feels a bit too pushed forward. Have got a shorter stem to try, but am wondering if longer forks with bigger rake would help more. Was going to get an lnbred 29er to replace my 853 lnbred, but got the Kona ‘cos it was £100 cheaper. Now they’re £60 off,can’t help thinking l should get one, as l’m assuming geometry would be better.Posted 5 years ago
Rake is an angle – offset is measured in mm
If it rides OK fine. IMO in theory the offset shuld be different for a 29r but brant for one said IIRC tht the difference was not worth worrying about.
Of course the amount of offest you need depends on the head angle ‘cos what its doing is altering the amount of trail you have
the stem will make no difference to the steering geometry
Posted 5 years ago
In the bicycle world the two are often confused and “rake” used when “offset” is what is really meant.
Rake is the steering head angle, offset is the distance the wheel spindle is carried ahead of the steering head but for some reason in the bicycle world this has got muddled.Posted 5 years ago
Previous discussion on this herePosted 5 years ago
cynic-al – Member
I’ve never head of head angle being called rake, only offset.
Well think about it – rake as a word refers to an angle or slope
to incline from the vertical, as a mast, or from the horizontal.
inclination or slope away from the perpendicular or the horizontal.
I don’t know why its used / confused like this in the bicycle world but it is. far better to refer to steering angle, offset and trail to avoid confusion.
Posted 5 years agoclubberMember
Rake in the bike world is not the same as rake in the motor bike world. You can argue all you like about which is technically right but we’re talking bikes and for bikes, it’s what’s shown in cooie’s pic.
As TJ said using the term ‘offset’ is much less likely to be confused if you’re talking to someone who also rides motorbikes.Posted 5 years ago
As I say its a bit of confusion thus referring to steering head angle, offset and trail and not using the term rake would helpPosted 5 years agoclubberMember
You’ll get used to the geometry on older 29ers but for me, the latest designs are the difference between bikes that handle ok but to me at least didn’t feel great on twist stuff to bikes that essentially handle as well as any other (26″) bike.
IIRC original 29er forks were 38mm offset while the newer designs are 45ishmm (and Gary Fisher/Trek G2 is 51mm)Posted 5 years agojamesoSubscriber
Basically there’s more offset on many newer 29er forks (around 45-52mm) to account for a slacker HA (eg 70-71 ish compared to early 71.5~72 degree bikes) that avoids your weight being too far fwd or the front-centre being too short compared to the often-long rear centre, a common complaint of early 29ers. More offset also keeps trail from getting too long on bikes with a slacker HA.
But there’s no solid reason in this since a bit slacker-still HA with less fork offset (around 40-45mm) gives a similar trail figure and similar relationship between bar, BB and front axle. ie What comes first, offset, trail or HA? )
41mm rake can still work fine, if you wanted less trail (lighter steering at expense of some stability) just add a longer-offset fork. Maybe not on a 2006 29er, i guess the HA’s closer to 72 than 70?
There’s sod all wrong with a 72 HA / low offset fork on a 29er BTW, there’s many being ridden and well-rated now with that kind of front end. So your current set-up may well be fine, just down to whether it’s ok for you or not.Posted 5 years ago
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