Giant 2014 Range!!!

[pharmaboy]

Currently riding a 26er anthem, I was getting excited about the new 27.5ers until I realized they've got a 69.5deg head angle. What's with that? A bit disappointing. Unless the 27.5 somehow doesn't need as sharp a head angle?

26er and 29er anthems both have 71 degree head angles.

Not half as important as you'd think. There's a couple of ways they can measure HA and give the result the market wants to hear. Further the effective head angle can be changed by the fork offset - given fox have different offsets to rockshox and giant report the same angles in specs, I wouldn't be hanging my hat on the specs they give.

 

[tomi_g]

Not half as important as you'd think. There's a couple of ways they can measure HA and give the result the market wants to hear. Further the effective head angle can be changed by the fork offset - given fox have different offsets to rockshox and giant report the same angles in specs, I wouldn't be hanging my hat on the specs they give.

I know HA (head angle) isn't the only factor in handling, but from my experience I find it is very important. I had a Kona Kula at one stage and it never cornered right. I rode it for a couple of years and didn't know what was wrong until I went back to a steep HA bike and straight away I could corner properly again. Also with my current bike (26er anthem), if I have the rear spring too soft so it sags and slackens the HA, it's the same deal - it just doesn't corner properly. You can't get the front wheel to dig in, it just wants to wash out. (when it's setup right it's awesome)

As for the rake of the fork, does that affect things the same way as the HA does? I can't say I fully understand how HA actually does increase front wheel 'dig-in' vs 'wash-out'..


How can they measure the HA differently as you say?

 

[tomi_g]

I've been trying to read up on the theory of all this head angle stuff (can only find a small amount of info online though) and It seem like the fork offset (commonly called rake) is also playing a part in the steering feel that I'm talking about. So just as pharmaboy said, there's probably more to it than just the HA number. I guess I'll stop worrying about the 27.5er anthem until I can try one!

Any feedback from 27.5 anthem owners yet?

 

[pharmaboy]

I know HA (head angle) isn't the only factor in handling, but from my experience I find it is very important. I had a Kona Kula at one stage and it never cornered right. I rode it for a couple of years and didn't know what was wrong until I went back to a steep HA bike and straight away I could corner properly again. Also with my current bike (26er anthem), if I have the rear spring too soft so it sags and slackens the HA, it's the same deal - it just doesn't corner properly. You can't get the front wheel to dig in, it just wants to wash out. (when it's setup right it's awesome)

As for the rake of the fork, does that affect things the same way as the HA does? I can't say I fully understand how HA actually does increase front wheel 'dig-in' vs 'wash-out'..


How can they measure the HA differently as you say?

They measure HA on a complete bike, so some options for them, is it with a a rider on the bike or not? With a 38mm offset fork or 46, or 51? Different tyre on the front versus the back? Is it the angle of the head tube versus the ground, or is it the effective head angle from the axle through the head tube? Is the spec from the small frame size or the large?

No standards unfortunately, so manufacturer specs are up to the manufacturer to provide, and very occasionally a magazine will actually measure them and publish ( this seems to be rare however)

Generally the steeper the head angle , the further forward your weight is in the attack position, weight is the biggest predictor of grip by far - more weight over the front, the more grip at the front and the less at the rear ( it's a zero sum game). Thus a slightly smaller frame for the rider provides more adjustable grip front to rear depending on body position.

The other interesting thing about the trance, is the slack seat angle, which means the higher the seatpost the further back you are so the more the bike sags going uphill, making the front end wander ( less weight at front).

IMO 29ers are in much less need of slack angles at the front generally, the axles are that bit higher so going OTB is that much more difficult.

Pb

 

[redbruce]

I've been trying to read up on the theory of all this head angle stuff (can only find a small amount of info online though) and It seem like the fork offset (commonly called rake) is also playing a part in the steering feel that I'm talking about. So just as pharmaboy said, there's probably more to it than just the HA number. I guess I'll stop worrying about the 27.5er anthem until I can try one!

Any feedback from 27.5 anthem owners yet?

While pertaining to road bikes, the principles apply to all bikes so this is as good an explanation as any:

http://cyclingtips.com.au/2011/02/the-geometry-of-bike-handling/

On bikes with suspension forks you also need to consider the changes (HA, wheelbase and weight distribution) due to fork compression as well.