Enduro/gravity bike suspension and geo

[Bos]

Nice. We were out Jonks way on Sunday for a party and boy was it raining. Trails must be mint after that.

 

Bos, what bike are you on? 

 

Foam grips are a no no for techncial riding. I tried them once and hated it. Some nice sticky ODI's are far and away the best. Currently I have Nukeproof Horizons on my Enduro which are also very good. 

 

Not sure that wider tyres work better on rocks. What are you running right now?

 

I'm on a Chinese carbon 135mm Horst-link varient. Looks a bit like a Trek EX. Reasonably updated geo. Really wanted a one bike quiver since I use to be into marathons for a couple of years.. Got that last year and then upgraded wheels and fork for Christmass. I found as it became more capable, I rode less distance and more fun stuff and I just wrote off tires and rims, so I decided, the hell with it, I'm letting go and going back over to the dark side Its been a fun journey.

 

Speaking of Kinematics..

I quite like the Horst link. I have had VPP and Singlepivot's before. The HLink is incredibly sensitive and active with minimal feedback, so much so that I really use the middle position on my Fox DPS rear shock a lot. Pretty much only open her up for downhills. Makes the bike feel like I went from a 110mm to 135mm instantly. I'm pretty happy with the rear I must say. I hope to see some options similar to what Scott is doing available aftermarket. Reducing the volume is really the best way to make a bike feel like a shorter travel version since it doesn't mess with small-bump sensitivity etc. 

 

Regarding the Grips, Heck yes. I'm getting some real rubber. Will look at those options.

My Front tyre is a 2.25 IBEX on a 30mm ID rim. The tyre is pretty good, I quite like it. I will replace with wider once worn out though. 

Got a couple of upgrades to sort out and a family to feed so its a work in progress. I feel like its a capable enough for what I need and can build on it..  

[Bos]

@ Headshot. Its made by a ICAN and they called it the P8.. 

[Headshot]

After fighting off most of a severe snot sinus bug I managed to get out on the Kirstenbosch XC loop yesterday afternoon. My bike is set up in the high position, around 35% sag and 26 psi in the Aggressor front tyre. With this set up it pedals well enough to almost never need the pedal lever on the shock. 

 

I took it down the same track I experienced the big front wheel slide with the Butcher. I didnt notice any lack of grip there but interestingly started to sense that the tyre gives a bit but never lets go enough to need a serious correction. Its predictable once you get used to it. One of the reviews I read mentioned this trait. While the time proves nothing really, I did get a PB down the slithery Newlands forest heep track descent which may point to greater confidence in my front tyre, or a relative lack of traffic, or both.

[Steven Knoetze (sk27)]

I will not lie and say I have read through this entire thread but I do have a geometry question.

My bike is setup up with the same travel suspension as per said manufacturers geometry chart yet I get different angles for my head angle and seat tube angle.

Why would this be?

Yes the tyres and rims may differ, could it be this?

More my own internal curiosity than anything.

I am also using an android app called AngleMeterPro2 so there is the inaccuracies of said app to consider too.

Anyway, any feedback appreciated.

[Steven Knoetze (sk27)]

Double post  

Edited February 13, 2019 by Steven Knoetze (sk27)

[Headshot]

And following on from the Chromag HT monster truck in teh other thread, there wa a heated debate on PB re how a long travel fork will or wont work on a hardtail. Some rather misguided opinions being expressed. Along teh lines of, on steep stuff, the front will go too low and you'll go over the bars. 

 

My point was that a dual suspension biks rear suspension extends on descents to some extent anyway and that my experience does not bear this out at all. What do you long travel HT riders say?

[Hairy]

My LTHT only has a 160mm fork fitted and rocks in at a supposed 65deg HA. Never felt like this was ever an issue.

 

The other factor is that the long travel fork would / should hopefully be a fork of decent quality, a decent quality fork does not just blow through it's travel, so the full extent of the travel will only be used on hard compression's, so the bike general geo should be constant most of the time.

 

And following on from the Chromag HT monster truck in teh other thread, there wa a heated debate on PB re how a long travel fork will or wont work on a hardtail. Some rather misguided opinions being expressed. Along teh lines of, on steep stuff, the front will go too low and you'll go over the bars. 

 

My point was that a dual suspension biks rear suspension extends on descents to some extent anyway and that my experience does not bear this out at all. What do you long travel HT riders say?

[Headshot]

I will not lie and say I have read through this entire thread but I do have a geometry question.

My bike is setup up with the same travel suspension as per said manufacturers geometry chart yet I get different angles for my head angle and seat tube angle.

Why would this be?

Yes the tyres and rims may differ, could it be this?

More my own internal curiosity than anything.

I am also using an android app called AngleMeterPro2 so there is the inaccuracies of said app to consider too.

Anyway, any feedback appreciated.

Tyres and wheels do make a slight difference. Also be careful of seat tube angles - they quote real and effective angles and I don't even pretend to undertsand how they are measured. 

[Headshot]

My LTHT only has a 160mm fork fitted and rocks in at a supposed 65deg HA. Never felt like this was ever an issue.

 

The other factor is that the long travel fork would / should hopefully be a fork of decent quality, a decent quality fork does not just blow through it's travel, so the full extent of the travel will only be used on hard compression's, so the bike general geo should be constant most of the time.

Precisely my experience with the 160 Pike on mine. Your set up is likely to be a bit stiffer up front to compensate for the sag factor but even so mine is still comfy and I never have issues even with a 70mm stem...

[Hairy]

70mm stem .... ROADIE ROADIE ROADIE!

Precisely my experience with the 160 Pike on mine. Your set up is likely to be a bit stiffer up front to compensate for the sag factor but even so mine is still comfy and I never have issues even with a 70mm stem...

[Steven Knoetze (sk27)]

 

So the chart lists my HA at 65.6 and STA at 72.8. I will assume by high and low they really mean low and X low depending on where the dog bones are.

My measurements are HA at 63 and STA at 68. So slacker at the front and with a steeper STA. Both things I am happy with, just curious as to why the difference.

I run a 2.5 front and 2.5 rear so possibly they do their measurements using say 2.3 or 2.4 both front and back??

68deg compared the charts 72.8deg means my STA is slacker, means climbing is harder, correct?

 

I measure by holding the phone flat against the stanchion and the seattube at the rear, this measurement is correct? I make sure everything is flush and bike is level too, standing straight up.

[Headshot]

70mm stem .... ROADIE ROADIE ROADIE!

I found a pic of me from the 1990's rocking a Giant ATX with a 120mm 25 dia stem, yesterday. No wonder it was harder to progress your riding back then, even a modest dh must have been scary.

[Headshot]

68deg compared the charts 72.8deg means my STA is slacker, means climbing is harder, correct?

 

Yes quite correct - the way to overcome that  a bit is to run your saddle as far forward as possible, as little sag as is practical out back and slightly more than normal up front. 

[Captain Fastbastard Mayhem]

Evil-Insurgent-Geo160.png

 

So the chart lists my HA at 65.6 and STA at 72.8. I will assume by high and low they really mean low and X low depending on where the dog bones are.

My measurements are HA at 63 and STA at 68. So slacker at the front and with a steeper STA. Both things I am happy with, just curious as to why the difference.

I run a 2.5 front and 2.5 rear so possibly they do their measurements using say 2.3 or 2.4 both front and back??

68deg compared the charts 72.8deg means my STA is slacker, means climbing is harder, correct?

 

I measure by holding the phone flat against the stanchion and the seattube at the rear, this measurement is correct? I make sure everything is flush and bike is level too, standing straight up.

Answer to the seat tube difference - you're measuring actual, whereas they list effective, by drawing a line between the BB and the seat post when the saddle is level with the bars. Seat tube kinks, so eff will always be different to actual.

 

Head angle - Evil specs their bikes with a fork of a certain Axle to Crown height. if you have a fork with a lower A2C, you will have a steeper HA. If you have a fork with a longer A2C, you will have a slacker HA. Not all 160mm forks have the same A2C measurement. 

Edited February 13, 2019 by Captain Fatbastard Mayhem

[Steven Knoetze (sk27)]

68deg compared the charts 72.8deg means my STA is slacker, means climbing is harder, correct?

 

Yes quite correct - the way to overcome that  a bit is to run your saddle as far forward as possible, as little sag as is practical out back and slightly more than normal up front. 

 

Turning my rear DHR the right way round might help too.........

[Steven Knoetze (sk27)]

Answer to the seat tube difference - you're measuring actual, whereas they list effective, by drawing a line between the BB and the seat post when the saddle is level with the bars. Seat tube kinks, so eff will always be different to actual.

 

Head angle - Evil specs their bikes with a fork of a certain Axle to Crown height. if you have a fork with a lower A2C, you will have a steeper HA. If you have a fork with a longer A2C, you will have a slacker HA. Not all 160mm forks have the same A2C measurement. 

 

I would assume Trailtech would sell the correct A2C.

But it is everything I thought, except for the effective STA, don't see why they would list this as opposed to the actual STA.