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Hello all. Browsing the web for cheap Pikes, as you do, I noticed many off the best priced ones are offset x or y.
As I understand it the offset is on the crown and I assume it slackens the angles a bit or lengthens the wheelbase without extending the chainstays? Regardless of what it actually does what would be considered 'standard'? Would no offset be the norm or would one of offsets be the usual standard?
I ask as I'm happy with my bikes geometry really so don't want to push the button on a fork that could bugger it up. Thanks in advance.
Nope the offset is at the axle. It's the difference between where the axle actually is (horizontally) compared to where it would be if the forks has no offset. I guess that's a reciprocal definition. It's horizontal offset.
More offset = snappier steering as the difference.
Brilliant stuff Matt, thanks.
Shows how out of touch I am as the last time I heard about offset was in the mid 90's when it was the crown they were on about!
Nope the offset is at the axle. It's the difference between where the axle actually is (horizontally) compared to where it would be if the forks has no offset. I guess that's a reciprocal definition. It's horizontal offset.
I'm fairly certain that the offset variations are done at the crown, so that the lowers can be common between the various models as they're much bigger parts. Much of the offset comes from the forward position of the axle on on the lowers though.
Longer offset reduces trail and thus quickens steering despite lengthening front-centre and wheelbase - best on slacker bikes. The larger the wheel, the greater the trail for a given head angle, hence the increased offset with larger wheels to allow less steep head angles with big wheeled bikes.
Std Rockshox are 46mm offset, but I think Pikes come in either 46mm or 51mm in the 29er versions. Go for the 51mm. I noteced a significant improvement in the feel of the handling of the bike (no real world inprovement of course, just how it feels). The only downside i've noticed is the steering can be a bit flip-floppy on steep climbs when the front end is lightly loaded.
After reading the link above I think it'll be the 46mm for me. Don't need the steering quickening and don't want the ride on tight, twisty trails compromised.
After reading the link above I think it'll be the 46mm for me. Don't need the steering quickening and don't want the ride on tight, twisty trails compromised.
That link makes no sense though. You're talking about decreasing trail by 5% and increasing wheelbase by less than 0.5%.
I'm fairly certain that the offset variations are done at the crown, so that the lowers can be common between the various models as they're much bigger parts. Much of the offset comes from the forward position of the axle on on the lowers though.
Could be, I probably spoke outside the envelope of my knowledge there.
That link makes no sense though. You're talking about decreasing trail by 5% and increasing wheelbase by less than 0.5%.
The first comment on the page says "the explanation is good, but the wheelbase issue is a specious argument (IMO). Pull out a ruler and look at how much 5 mm would change your wheelbase -- essentially none. However, trail is a trigonometric function so small changes in offset can have profound effects on trail and, consequently, handling. I humbly suggest that any difference felt between two fork offsets is due to changes in trail and not wheelbase."
I don't know either way myself, just cut and pasting.
@chest my Pikes are 46mm, run at 140mm on a 29er HT, which should put the head angle at 67 degrees. Anyway whatever it is, it works well for me. I'm in Surrey Hills if you want to try before you buy.
Cheers Matt and thanks for the offer. Bit far to travel from Yorkshire though. It seems to suggest that 46mm is about standard so that's good enough for me.
I humbly suggest that any difference felt between two fork offsets is due to changes in trail and not wheelbase."
I'd agree. I see the longer offset forks as providing a more 'neutral' lower-speed handling feel on slacker bikes that feel good everywhere apart from climbs, low-speed tech and some corners - places where the flip-flop steering typical of slack/long-trail bikes can be a negative.
apart from climbs, low-speed tech and some corners - places where the flip-flop steering typical of slack/long-trail bikes can be a negative.
That pretty much covers any slight weak points of my bike so I certainly don't want to make it worse.
It seems to suggest that 46mm is about standard so that's good enough for me.
That was pretty much my thought process too.
More offset should make it better. To clarify my point,That pretty much covers any slight weak points of my bike so I certainly don't want to make it worse.
ie longer trail (slacker) bikes can have that floppy-steering effect at low speed. More fork offset/rake reduces trail and reduces that effect.providing a more 'neutral' lower-speed handling feel on slacker bikes that feel good everywhere apart from climbs, low-speed tech and some corners
Depends on what the bike is designed for. A trek or a Salsa is probably designed to run best with 51mm offset.
51mm forks are very hard to find in the UK
Depends more on the bike geo than the brand, but yes. And what one person likes another won't so the usual 'there's no ideal combo' disclaimer applies as usual.
Depends on what the bike is designed for. A trek or a Salsa is probably designed to run best with 51mm offset.
Aye, as I only found out after the event - running a 46mm offset fork on an El Mar, which doesn't noticeably handle like an oil tanker.
Would be interesting to see if I can tell the difference with a 51mm offset though.
The offset is done at the crown.
Ibis state that the Ripley should be built up with 51mm offset forks.
However as I'm running mine with a 140mm fork up front I chose a 46mm offset. My thought being it shortens the wheelbase slightly.