So I am experiencing the front wheel tucking under on low speed steep descents and dumping me on the deck. What I have altered is, Muller the back wheel and left the flip chip in its lower setting because I thought it would be better for recent Alps trip. I got thrown off three times yesterday so I thought I would ask what you guys think? Original head angle is 63°. From my mechanic days it seems like the caster angle is wrong?
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Geometry experts please!
- Thread starter Bones
- Start date
militantmandy
Well-known member
Perhaps you are riding a bit far off the back of the bike on the steeps, which in turn is reducing your front grip. If you're then using a lot of front brake because it's really steep, then it could be easier to lock the front wheel. All of which could be exacerbated by having a slacker than normal fork. If any of that makes sense, then I would try to focus on bending your elbows to force you closer to the front wheel.
ebikerider
Active member
Put the 29er rear wheel back in and ride the same terrain and note how the handling feels. If it was originally 63 degree's and you have just dropped a 27.5 rear in there the head angle could be 61.? which is getting to be too slack imo for the majority of terrain.
militantmandy
Well-known member
More like 62 and a wee bit I would have thought, still a very slack bike though.
- Thread starter
- #7
I destroyed the original wheel and because of the flip chip I went down the mullet route. Interesting that you consider the head angle to be wrong though. I will try the easiest option and flip the chip to the higher setting though
In addition to making your head tube angle much too slack, going mullet will also shift the weight balance of your bike back. So as per the advice from the guys above you need to make your head angle steeper and make saddle and bars changes to move your centre of mass forward. I would also advise always using the ready position when descending rather than staying on the saddle.
Bones said:
Sitting on the saddle will move your weight back and unweight the front.
- Thread starter
- #10
Advice taken onboard. I will rotate the bars forward and shift the saddle along the rails. I am guilty of not moving around as I should. I've got a new hire bike all next week as away, so will see how that is set up. If I can't sort it then it'll go back to a 29"
This.
When descending do not stay seated, to be able to steer the front end must be weighted. As long as the front end is going where you want the back end will follow.
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- Thread starter
- #12
Yes I have to agree. I have it in my head that seated keeps the centre of gravity down and if I come off it won't hurt as much because I'm closer to the ground anyway 
I might also try some flat bars instead of the riser ones fitted .
I might also try some flat bars instead of the riser ones fitted .
militantmandy
Well-known member
Without wishing to be patronising, it sounds like your issues are much more connected with your riding than with your geo or bike set up. Working on the fundamentals of body position will yield far more results that tweaking bar angles. I think it's important to recognise that not all things can or should be tackled by making changes to the bike.
If you are that old and knackered, you need to work on your fitness first and stop wasting your time and money on bike parts and will only result in minimal differences to those who are riding well enough to notice them. Watch a WC DH race an count the number of seconds the riders sit down while riding down a 3-4 minute track. Lower your expectations and increase your enjoyment!I'm old and knackeredmy legs hurt to much if I have to stand up a lot. I am relying to much on the fox 38s keeping things in order but I need to shift my arse to help them out
Either stand up and your legs hurt, or stay seated and crash.I'm old and knackered
Blunt but true.
I"m 76. After 5 minutes downhill my thighs burn but it's either that or sit down and have a horrible crash. If the thigh burn gets to the point where I can't take any more then I stop and have a rest and drink some fluid.
As @KnollyBro says, bike parts won't fix your problem.
You need to put more weight over / on the front wheel. Try bending your elbows and leaning forward. I understand your problem, sitting is not great but look at getting some weight forward. Maybe slide your saddle forward on its rails and or get a longer stem.
Age is no reason to allow leg pain to stop you riding better! Past injury may be a different issue though.
Rider mass dominates a bike...even a 25kg emtb given that most riders 3 times that mass or more. You need to be able to move your weight forward and back and side to side.....and you can only do that dynamically stood on the pedals. (I am 73 and my preferred type of riding is downhill so I spend very little time in the saddle).
Most of the strain when riding on the pedals is on your quads and knee joints. Keeping your feet almost centred on the pedals rather than with balls of your feet on the pedal spindles gives you more control and less strain on ankles.
So maybe one option for you is to do some gym work on your quads.
Rider mass dominates a bike...even a 25kg emtb given that most riders 3 times that mass or more. You need to be able to move your weight forward and back and side to side.....and you can only do that dynamically stood on the pedals. (I am 73 and my preferred type of riding is downhill so I spend very little time in the saddle).
Most of the strain when riding on the pedals is on your quads and knee joints. Keeping your feet almost centred on the pedals rather than with balls of your feet on the pedal spindles gives you more control and less strain on ankles.
So maybe one option for you is to do some gym work on your quads.
Plummet
Flash Git
Can you show pictures of your bike and set up?.
Ps if you have fox 38 and 63 head angle. It's most likely technique than equipment.
And Or terrible suspension set up. Rebound too fast on the rear combined with fork to soft on the front. The front fork dives too deep and the rear bounces back too fast your technique being slightly off will bounce you over the front.
Or Are you sitting down riding chunky stuff then wondering why you get bucked over the front?
Ps if you have fox 38 and 63 head angle. It's most likely technique than equipment.
And Or terrible suspension set up. Rebound too fast on the rear combined with fork to soft on the front. The front fork dives too deep and the rear bounces back too fast your technique being slightly off will bounce you over the front.
Or Are you sitting down riding chunky stuff then wondering why you get bucked over the front?
That’s a sweet ride, looks dialed in. Best path as discussed is getting in the attack position on the downs and be mobile with enough weight over the front.
I’ve never tried going down steep stuff seated but maybe try running less than the usual sag up front? Just spitballing here as that causes its own issues with balancing out your suspension with a rearward bias. It can also cause some deflection issues and small bump troubles.
I went through a similar issue learning to ride steep downhills trails on a moto. When it was so steep that the bike would start to go faster than I wanted and I couldn’t use the brakes to slow down, I would get tentative and grab a fistful of front brake and tuck in the front end. It took me getting aggressive and off the brakes to attack the downhills before I regained control and stopped dumping the bike.
I’ve never tried going down steep stuff seated but maybe try running less than the usual sag up front? Just spitballing here as that causes its own issues with balancing out your suspension with a rearward bias. It can also cause some deflection issues and small bump troubles.
I went through a similar issue learning to ride steep downhills trails on a moto. When it was so steep that the bike would start to go faster than I wanted and I couldn’t use the brakes to slow down, I would get tentative and grab a fistful of front brake and tuck in the front end. It took me getting aggressive and off the brakes to attack the downhills before I regained control and stopped dumping the bike.
Which is why I now have Pedaling Innovations Catalyst One pedals - no more pedalling or standing on the balls of my feet! After I took the time to reconfigure the pin layout and lengths to get them just right they are indeed game changers. Also adjusted seat height and position.
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I also prefer concave pedals (which Pedaling Innovations Catalyst One pedals are). Previously I used Deity Tmacs and before that DMR Vaults.
Who set up your bike? Never run your brake line on the out board side of the fork lowers. If you put the bike down hard, you can blow out the brake line Getting it caught between the fork and a hard object. Run the line inside next to wheel.
Your grips are a main issue. You weight the front wheel through the palm of your hands. Having those flat grips while you are seated means you can’t push/weight the front wheel. Angle the grips so you can push on them.
steve_sordy
Wedding Crasher
In the beginning....(2008) on my first mtb, a Kona Kula hardtail, and on my very first ride after an "Introduction to MTB" course.
The first time I tried riding down a hill with my arse firmly planted on the saddle was my last ride for several weeks! I was going as fast as I dared, probably about 20mph down a rough farm track about ten miles from home. The hole I rode into that the fork soaked up was not so kind to the back end of my hardtail. As I exited the hole, the rear kicked up and launched me into a Superman over the bars. I landed flat onto rough shale/gravel, bounced and then slid for what felt like ages, but was probably only a second or two. My knees, that bit above the knees, both elbows and that bit below the elbows, were all deeply gouged. I got a deep blue horseshoe shaped bruise on my front that followed the outline of my sternum and ribs. My helmet was split in two, the peak ripped off, my specs were driven into my face and I'm pretty sure that I was briefly knocked unconscious. I came to and just laid there thinking "someone will come to help". But there was nobody about, I wasn't even too sure exactly where I was. Nobody came of course, so after a while feeling all pathetic, I manned up and rose to my feet to inspect the damage. Absolutely no damage to my bike at all, not one bit!
I decided to carry on with my ride as it would be the shortest way home. When I arrived, there was blood pooling in my socks and gloves and running down my shorts as it dripped off my elbows. My face looked a bit of a mess and my glasses were looking in different directions. My Mother happened to be staying with us that week and she took one look at me and said that the last time she saw me like that was when I came off my bike when I was four years old (I still have the scar under my nose, with the cinders still in it).
It was ten days before I could wear long trousers and long-sleeved shirts without bandages. My glasses had to be straightened by the optician and of course I had to buy a new helmet! (There is always a silver lining!)
I never tried riding downhill sat down ever again! Lesson well and truly learned!!
The first time I tried riding down a hill with my arse firmly planted on the saddle was my last ride for several weeks! I was going as fast as I dared, probably about 20mph down a rough farm track about ten miles from home. The hole I rode into that the fork soaked up was not so kind to the back end of my hardtail. As I exited the hole, the rear kicked up and launched me into a Superman over the bars. I landed flat onto rough shale/gravel, bounced and then slid for what felt like ages, but was probably only a second or two. My knees, that bit above the knees, both elbows and that bit below the elbows, were all deeply gouged. I got a deep blue horseshoe shaped bruise on my front that followed the outline of my sternum and ribs. My helmet was split in two, the peak ripped off, my specs were driven into my face and I'm pretty sure that I was briefly knocked unconscious. I came to and just laid there thinking "someone will come to help". But there was nobody about, I wasn't even too sure exactly where I was. Nobody came of course, so after a while feeling all pathetic, I manned up and rose to my feet to inspect the damage. Absolutely no damage to my bike at all, not one bit!
I decided to carry on with my ride as it would be the shortest way home. When I arrived, there was blood pooling in my socks and gloves and running down my shorts as it dripped off my elbows. My face looked a bit of a mess and my glasses were looking in different directions. My Mother happened to be staying with us that week and she took one look at me and said that the last time she saw me like that was when I came off my bike when I was four years old (I still have the scar under my nose, with the cinders still in it).
It was ten days before I could wear long trousers and long-sleeved shirts without bandages. My glasses had to be straightened by the optician and of course I had to buy a new helmet! (There is always a silver lining!)
I never tried riding downhill sat down ever again! Lesson well and truly learned!!
Maybe it's just the photo, but your fork angle looks far steeper than 63 degrees. Couple that with riser bars rotated forward, sitting on a raised saddle instead of saddle dropped or being behind it? Perhaps a perfect recipe for too much weight on the front while descending, causing the fork to dive too much and tuck?
Good luck on finding a better setup.
Cheers.
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