I bought a Helix, the Lynskey geometry says the frame was designed for the 43 rake fork, I have a 45 rake Enve laying around, will the 2mm rake difference totally change the ride feel?

This might help you make an informed guess. https://www.cyclingtips.com.au/2011/0...bike-handling/

Don't neglect the axle to crown measurement, either.

Nothing drastic but, a slightly longer wheelbase, in all reality, no, not really.

It won't make a big difference but it will reduce trail and contribute to quicker steering.

Trail is often misunderstood...especially in the context of fork rake...or at least easily confused. See pic below. Visualize the difference of increasing the fork rake i.e. moving the axle center forward which reduces the distance at the pavement where the lines you see intersect with the road...which by definition is trail. Less trail = quicker handling. Trail is basically castor...like on a shopping cart wheel or an automobile. When you turn the wheel, you are physically lifting the bike by the lever of trail...and this lever is the self centering ingredient of steering...or resistance to turning is another way to consider it. So if you reduce this lever length, then the front bike wheel will be less resistant to turning aka turn more easily.

So if you believe your handling is a touch on the twitchy side...don't make this change. If you believe your bike handling can tolerate a slightly quicker turn in, you should be OK with increasing fork rake slightly.

HTH.

Nice! I thought I knew what is the effect of trail regarding handling, but it never occurred to me to ask why. Your explanation of lifting the bike with a lever is a totally new concept to me. Thanks so much!

Robert

BTW, OP, my best riding buddy has a Helix and just loves it.

Robert

Hi Robert...
Yeah...trail is basically the concept of castor and a prevalent component of steering...referred to in automotive engineering as returnability also contributing to tracking and on center feel. If you thinking about the arc of a front wheel axle which doesn't share the same axis with the head tube angle and contact patch, as the axle turns, the physical weight of the bike is lifted. It is this weight that contributes to the steadiness for on center tracking. Lack of it of course is the opposite and contributes to more 'nervous' steering.

Drag bikes are very nimble.

Thanks guys for the replies, I wouldn't know rather my bike will be stable or twitchy because I never had a 43 rake fork, I have nothing to compare to, I will put my 45 rake fork on to the bike for now, just to see how it goes.

Are you speaking of drag motorcyles? Don't know of any drag bicycles per se.
As to drag motorcycles, no...they are not nimble. Steering is deliberately slowed not only by increased trail but by lengthened wheelbase.
If they weren't, there would be lot more crashes.

Bingo.

I've had everything between 40 and 48 on my current bike which came with 43. 48 was noticably faster but really no functional difference. I bet 43 to 45 would be hard to notice without back to back comparisons.

Yeah. We're talking 2 mm difference. Mere mortals will never feel the difference.

2mm when it comes to rake isn't inconsequential. I believe the OP may feel the difference. OP...when you get the 45mm fork mounted, please come back and give us your impressions.

I do agree however the change would be manageable as ivan stated. One thing about steering is...I wrote to Sheldon Brown about stem length before his unfortunate passing....he said there is a pretty wide spectrum of handling from tandems to upright angle road bikes and we quickly adjust to these differences. I agree.