Gravel Geometry, Lowering Trail: Angleset vs. Offset

[jwin]

I've got a Diamondback Haanjo Carbon (53cm) that I'm trying to make it somewhat road worthy for a temporary period of time. I put on some 700x36c file tread tires and handling (which was already a bit wonky) got even more wonky.

From what I've gathered this is due to it's very high trail figure (80mm) causing it to steer more like a motorcycle than I'd like. Based off of this article: https://www.rodbikes.com/articles/phinney-fork/rake-trail-gravel-bikes.html, I'd like to try and reduce the trail number either by:

- Cane Creek Angleset to steepen the head angle by 1 deg.
- Change the fork to a higher offset

I have two questions:

1. Is there any downside of going to a higher offset vs. an angleset? Higher offset will help maintain a larger front center, reduce toe overlap, and

2. How much trail should I shoot for and based on that, what fork options do I have? My initial thought is to shoot for a trail figure of 65-70mm with a corresponding fork offset in the high-50mm's. There doesn't seem to be many options in this space, though Rodriguez Cycles does have an aluminum one with 55mm.

Thanks for the feedback before I drop some $$!

[pbarry]

It’s a conundrum I share. :) What’s the A-C of that DB fork? Looks like it might be 385, with the 37c tire width shown on their site. Options are pretty limited for that length. If it’s 395, there’s the Seven Matador, (55mm) and 3t Luteus @ 50mm. Ritchey Adventure is 393 and 50mm.

Mid 60’s for trail is a good spot to be imo. I’m at 77 with a Lauf fork.

[ryker]

FWIW one of your options lengthens the front-center and wheelbase while the other decreases both.

[robt57]

Try 28mm tires.

But if you can't get trail to 60ish, forget it I say.

[Old School]

quick non-answer:

I am busy at work (fortunate) so I cannot go too deep, but in my experience.

Fork offset and head tube angle are two completely different things, but the effect FEELS surprisingly the same. If I had a billion dollars, I would buy one of the new forks with the changeable offset (for lack of a better term), but changing the headset angle is cheaper and faster. IF and only IF you can get the parts from England. (https://www.workscomponents.co.uk) I would hesitate to buy any other brand.


https://www.cxmagazine.com/wp-content/uploads/2020/01/cervelo-aspero-gravel-bike-carbon-sram-axs-img_6834-cxmagazine-ay_1.jpg

[jwin]

It’s a conundrum I share. :) What’s the A-C of that DB fork? Looks like it might be 385, with the 37c tire width shown on their site. Options are pretty limited for that length. If it’s 395, there’s the Seven Matador, (55mm) and 3t Luteus @ 50mm. Ritchey Adventure is 393 and 50mm.

Mid 60’s for trail is a good spot to be imo. I’m at 77 with a Lauf fork.

The A-C is 395 so I have some options. The Ritchey Adventure has all the features I want, but I just wish it was 55mm offset. I'm not sure whether getting down to 74mm trail with 50mm offset is worth the cost...

Or I just buy a new bike :p

[jwin]

quick non-answer:

I am busy at work (fortunate) so I cannot go too deep, but in my experience.

Fork offset and head tube angle are two completely different things, but the effect FEELS surprisingly the same. If I had a billion dollars, I would buy one of the new forks with the changeable offset (for lack of a better term), but changing the headset angle is cheaper and faster. IF and only IF you can get the parts from England. (https://www.workscomponents.co.uk) I would hesitate to buy any other brand.


https://www.cxmagazine.com/wp-content/uploads/2020/01/cervelo-aspero-gravel-bike-carbon-sram-axs-img_6834-cxmagazine-ay_1.jpg

This is good to know. I would love to buy a flip-chip fork. The Columbus Futura Cross has a 47/52mm flip chip, but no fork mounting features :/. The GT Grade's new fork has a 55mm/70mm flip chip!! But I don't think I can buy it stand-alone.

[pbarry]

Rondo Ruut fork has the flip chips, but not available separately. One sold abt a month ago on eBay for cheap-ish $.

[false_Aest]

Angleset to 71 degrees
50mm offset fork
30mm tires

Should bring you into the mid 60s for trail.

But because nothing about a bike is independent, you still might not get what you're looking for.

[robt57]

Angleset to 71 degrees
50mm offset fork
30mm tires

Should bring you into the mid 60s for trail.

But because nothing about a bike is independent, you still might not get what you're looking for.


Kinda what I said in less words pretty much... ;)

[jwin]

Kinda what I said in less words pretty much... ;)

Yeah, it's almost like at what point do I give up and just sell the bike. Buy a Spesh Diverge and call it a day. Le sigh.

[pdmtong]

quick non-answer:

I am busy at work (fortunate) so I cannot go too deep, but in my experience.

Fork offset and head tube angle are two completely different things, but the effect FEELS surprisingly the same. If I had a billion dollars, I would buy one of the new forks with the changeable offset (for lack of a better term), but changing the headset angle is cheaper and faster. IF and only IF you can get the parts from England. (https://www.workscomponents.co.uk) I would hesitate to buy any other brand.


https://www.cxmagazine.com/wp-content/uploads/2020/01/cervelo-aspero-gravel-bike-carbon-sram-axs-img_6834-cxmagazine-ay_1.jpg


A friend recently got that headset angle changer from works and a new fork. Changed the whole feel of the bike

[spoonrobot]

I have the same size Haanjo. Honestly I think you'd be happiest with just selling the bike and getting something with geometry that meets your preference. I tried different forks but the flop is always going to be there so it never quite feels "good" even if you can get the trail down.

I rode mine with a 60mm offset fork from Performance for while with 38mm slicks - gave me 62mm trail and 21mm flop. It was ok but not great, still floppy but less precise steering feeling. Still had quite a bit of lean and didn't descend great.

Honestly I'm happier with the bike running a bigger tire in the front (44mm Snoq. Pass from Compass) and wider handlebars (50mm FSA Adventure) than anything else. Both these combine to reduce the tiller effect of high trail and allow easier/more comfortable leaning during cornering. Much less oversteer at speed as well. Still my least favorite bike for riding in the rain or on loose surfaces. Works great as a rando bike because it tracks straight as an arrow.

Although you could also change wheelsize. When I first got the bike I rode it exclusively with 650bx40mm tires - I thought it handled fine and really liked it. Didn't have any issues until I went to 700c. Something to consider.

[jwin]

I have the same size Haanjo. Honestly I think you'd be happiest with just selling the bike and getting something with geometry that meets your preference. I tried different forks but the flop is always going to be there so it never quite feels "good" even if you can get the trail down.

I rode mine with a 60mm offset fork from Performance for while with 38mm slicks - gave me 62mm trail and 21mm flop. It was ok but not great, still floppy but less precise steering feeling. Still had quite a bit of lean and didn't descend great.

Honestly I'm happier with the bike running a bigger tire in the front (44mm Snoq. Pass from Compass) and wider handlebars (50mm FSA Adventure) than anything else. Both these combine to reduce the tiller effect of high trail and allow easier/more comfortable leaning during cornering. Much less oversteer at speed as well. Still my least favorite bike for riding in the rain or on loose surfaces. Works great as a rando bike because it tracks straight as an arrow.

Although you could also change wheelsize. When I first got the bike I rode it exclusively with 650bx40mm tires - I thought it handled fine and really liked it. Didn't have any issues until I went to 700c. Something to consider.


Interesting. I’m still too green on geometry to understand exactly what is “wrong” with the Haanjo geo. You mention that even with an “appropriate” trail it still feels weird.

That said, I ran this bike for most of its life with 650b x 2.1 and while the outside diameter is very similar to the current 700x36 setup, I was quite happy with how it handled overall. It must have to do with the wider tires. I’m not exactly privy to why.


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[NHAero]

I considered buying one that was for sale here quite a while, back, and looking at the geo chart i thought it was way at the end of the bell curve and I chickened out, expecting what you've discovered. Really slack head angle and long trail.

[spoonrobot]

Interesting. I’m still too green on geometry to understand exactly what is “wrong” with the Haanjo geo. You mention that even with an “appropriate” trail it still feels weird.

That said, I ran this bike for most of its life with 650b x 2.1 and while the outside diameter is very similar to the current 700x36 setup, I was quite happy with how it handled overall. It must have to do with the wider tires. I’m not exactly privy to why.


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It's trail is too long for the size tires, top tube, stem and handlebar width. 80mm trail really requires 50mm+ handlebars, top tube (and what that entails) conducive to <70mm stem and tires 45mm or greater to get in the "average rider likes this" zone.

650b were knobbies?

Wider tires + lower air pressure + knobbies means you get more pneumatic trail which means it is "harder" to turn the handlebars so you do not engage much flop - instead intuitive counter-steer and lean is performed. I've also noted (probably after being primed reading BQ) that a smaller diameter wheel with a relatively heavier tire has more rotational inertia that contributes to less handlebar turn and more lean.

With slicks + higher pressure and relatively lighter weight tire, you get less pneumatic trail so it is "easier" to turn the handlebars which engages the flop, which is what feels weird.

[John H.]

What size is your bike?
Geometry seems wonky in general especially in smaller sizes.
Fork is under-raked, Head angle too slack.
Toptubes pretty short.

I agree that you could find a different bike that works better.

I have been riding one of my gravel bikes as a road bike of late. (with road wheels, 700x28mm tires and road gearing). It rides great as a road bike.
It is an Open in size medium with a 71 degree head angle and 50mm of fork rake.

[jwin]

The 650b’s were Thunderburts, so knobbies.

My bike is 53cm.

I guess I wonder if fixing the trail to mid-60s via fork offset would still produce strange handling, and if so - why?


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