Looking at some forks and they have a 51mm fork offset,

How would this affect the handling on a bike with a slack head angle?

cheers.

You won’t notice it.

I’m not sure anyone really knows!

Is it effect or affect ???

… “effect” on handling.

I think it speeds up the steering. Although I couldn’t tell you why.

If this is a 29er fork, that’s what you want. I would think for anything else it might not be.

It’s a question of how they’ll affect the handling but it’s hard to say what the effect will be!

affect is a verb, effect is (broadly) the noun of the same thing.

eg: a slack head angle affects the stability of a bike.

The effect of a slacker head angle is to change the stability.

and to the question:

http://forums.mtbr.com/general-discussion/what-fork-offset-all-about-343777.html

It is a 29er fork, the one fitted to the bike is a normal (Whats normal these days though) offset and Ive noticed a bit of wheel flop at low speed which is something that was picked up in the singletrack review too.

I think it speeds up the steering. Although I couldn’t tell you why.

Isn’t it because there’s a reduction in trail?

Remind me again what the advantage of a slack HA is – is it high speed stability or something else?

Someone has actually done an experiment with this, repeating the same bit of trail on the same fork with different offsets. Here.

the one fitted to the bike is a normal (Whats normal these days though) offset and Ive noticed a bit of wheel flop at low speed

If the old fork is ~42-46mm offset so the 51mm fork increases the offset, you might notice a little less flop at low speeds than you do now. It won’t be a dramatic change, more like a tweak similar to a half degree or so on the HA, that level of change.

Renton no offence but I think a lot of what you perceive to be happening is stuff you’ve read. Have you actually ridden it much? Your ad says you haven’t used them so I’d be surprised if you are noticing that much flop. How much is general getting used to the bike? How many hours have you put in on them? Tried changing your set up elsewhere?

No offence taken Stu.

It’s quite easy to feel the wheel flop mate even just moving the bike around in the garage mate. I’m slightly concerned by it at the bars and controls are banging into the top tube far to often.

I am going to ride it as is for a bit to be honest. I was just asking the question out of interest as when the time comes to upgrade I want to make sure I get the right fork.

I’ve ridden both 46mm and 51mm on a trek attached. The 51mm where more agile and could corner on tight single-track better. Fir trek 51mm is normal.

No offence taken Stu.

It’s quite easy to feel the wheel flop mate even just moving the bike around in the garage mate. I’m slightly concerned by it at the bars and controls are banging into the top tube far to often.

I am going to ride it as is for a bit to be honest. I was just asking the question out of interest as when the time comes to upgrade I want to make sure I get the right fork.
Fair enough Steve. I’m curious as well to know if it would make a discernible difference, just wondered if there’s easier options out there. You’ve had 29rs before from memory so you’re used to the way they handle.

Aye that is right bud and none have displayed this much wheel flop but then none of them were this slack at the front.

To quote the stw review ….

The only downside to Whyte’s new geometry ethos on the 529 is that it can feel a little sluggish at slower speeds, and the front wheel does exhibit more wheel flop on the climbs. But that’s a pretty acceptable trade-off in my opinion.

Hopefully it’s something I can get used to as it’s the most up to date bike I’ve ever had geometry wise.

I’d just try actually riding the thing instead of worrying about a review.
Moving the bike in your garage isn’t much of a refection on how it’ll handle when it’s being ridden as intended.

I’ve had 51 and then 46 on the same bike, any difference is marginal. Buy whichever one is the best deal

Now then. I’ve got shit fer brains but I’d like you to explain how a change in the relative position of crown and axle affects the position of your levers and shifters relative to your top tube. Intrigued.

I think op means the wheel is flopping more making that more of an issue?

Luckily my first 29er build has clearance…. Very luckily being my first carbon frame too! :-/

Mkay. Point taken.

oldnpastit – Member

I think it speeds up the steering. Although I couldn’t tell you why.

ratherbeintobago – Member

Isn’t it because there’s a reduction in trail?

Remind me again what the advantage of a slack HA is – is it high speed stability or something else?

Slack HA slows steering down.

Short stem decreases stability to compensate, but the wheelbase is still longer (doubly so if you keep reach to the bars the same by increasing the frame’s reach).

Increasing offset is a bit like shortening the stem. It just means you can make the bike even longer without the handling becoming a handful.

So (in theory) a 51mm offset will speed up steering response thisis?

I’m new to 29ers and thus offset effects…

Someone has actually done an experiment with this, repeating the same bit of trail on the same fork with different offsets. Here.

total opposite experience to mine with fork offsets, I prefer longer offsets – better weight balance on steep terrain and less feeling like the wheels going to tuck under when throwing my weight forwards during cornering.

Who the **** makes continual mid corner steering corrections anyway? Maybe my technique is whack, but I feel like more of my turning is done by countersteering on entry to a turn, my hips and by weight changes – and by setting up a corner properly and making one large movement.

Now then. I’ve got shit fer brains but I’d like you to explain how a change in the relative position of crown and axle affects the position of your levers and shifters relative to your top tube. Intrigued.

it probably had more to do with the flat bar that came on the bike. Ive since fitted a riser bar and the controls clear the top tube now, only just mind.

Slack HA slows steering down.

So does increasing wheel size (due to increased trail). Increasing the offset speeds it up again (by decreasing trail).

But slow steering is another way of saying increased stability, so what’s the point of slackening the HA then increasing the offset?

But slow steering is another way of saying increased stability, so what’s the point of slackening the HA then increasing the offset?

Because stability is largely related to weight distribution imo. Trail is a big part of it, but not all.

Bikes got slacker to get the weight and position right for more full-on riding, high flop / the feel of slackness became a sign of that because MTB forks had fixed offsets. Really slack bikes are stable if you’re riding like a top downhiller but in many situations (lower speeds, weaving through singletrack, climbing etc) they can be ‘unstable’ in a way due to steering flop bringing a kind of positive feedback into the steering – ie you go into a corner, the flop effect makes the bike drop into the corner more than intended and you need to react to bring it back onto the intended line, gets fidgety, just not in the way a ‘fast steering’ bike can be fidgety. The more used to the bike you are the less this happens but swap bike types a fair bit and you notice it.

Jameso thanks that makes sense.

So just out if interest if i fitted a 51mm offset fork to a bike that’s fitted with a normal offset fork would it changed the head angle and also would it change the wheelbase of the bike.

What’s a normal offset?

Offset won’t change any angles – it just throws the front wheel slightly further forward and so changes (marginally) the wheelbase – by a matter of mm

By changing the wheelbase (but only at the front wheel) you then get the increase in trail which gives benefits to steering

Changing the head angle can give a similar increase in stability but it doesn’t affect the steering feel.

Edit. These changes are likely to be so small that unless there is an inherent flaw in the bikes geometry then you just compensate for it as you learn to ride it

So (in theory) a 51mm offset will speed up steering response thisis?

Yes (because it reduces trail)

But slow steering is another way of saying increased stability, so what’s the point of slackening the HA then increasing the offset?

Yes, but think of it rather as increasing the wheelbase without affecting anything else. The short stem, long top tube, offset and head angle are all working together to deliver longer wheelbase without otherwise affecting the handling too much.

So just out if interest if i fitted a 51mm offset fork to a bike that’s fitted with a normal offset fork would it changed the head angle and also would it change the wheelbase of the bike.

Only by tiny amounts, but it would speed up the steering.

looking forward to rentons next adventure where he moves out of the garage and rides his bike around the garden…… or will he sell it, the plot thickens

Oh nice one …… Who are you ??

tbf, you do leave an open goal for such comments Rents.

Back in my student days I remember noticing how sluggishly my Vauxhall Nova handled when bump starting it. Sadly I couldn’t afford to upgrade the shocks but fortunately it never seemed as bad when I wasn’t pushing it due to a flat battery…

I know my ti29er was transformed when I fitted lower a-c rigid forks with 55mm offset (Jones), made it a fantastic ride and have left unchanged since.