My old xc bike is faster than my newer full suss :(
danlightbulb
Posts: 701
Hi all.
Ive posted recently about my Boardman Pro FS bike (27.5", 140mm front, 130mm rear, 14.3kg) feeling draggy on the trails. I thought it might have been the weight or tyres so I bought some new tyres and went tubeless. Im very impressed with the new tyres and it has helped a little I think and certainly made it feel better on the descents.
However yesterday I took my old Rockrider 8.1 hardtail (26", 100mm front, 12.8kg) out for a ride on the same trails. I got Strava PBs on some of the climbs without even really trying. It was loads faster, for considerably less perceived effort, on the flat singletrack and climbs. I could accelerate it far better and maintain momentum far better.
I am running considerably higher gearing on the Rockrider as well. 32-32 (2x9) is my lowest gear on that bike compared to 32-42 (1x11) on the Boardman. Despite this, my physical effort on the climbs felt easier and my legs were not running out of steam anywhere near as fast as on the Boardman. On the Boardman I am forced to sit and spin in lowest gear most of the time because my legs are done in trying to push a harder gear on it.
The downside was on the descents where the steeper angle of the Rockrider was noticeable and made it a bit sketchy on some steeper sections of the trail. I dropped the chain as well on a rocky section which never happens on the Boardman.
So Im left with a dilemma now. I enjoy hitting descents fast and securely but i also really enjoyed being able to maintain momentum on the flat and climbs yesterday on the xc bike. The trails I ride are a mix of features. How do I get the best of both?
Ive posted recently about my Boardman Pro FS bike (27.5", 140mm front, 130mm rear, 14.3kg) feeling draggy on the trails. I thought it might have been the weight or tyres so I bought some new tyres and went tubeless. Im very impressed with the new tyres and it has helped a little I think and certainly made it feel better on the descents.
However yesterday I took my old Rockrider 8.1 hardtail (26", 100mm front, 12.8kg) out for a ride on the same trails. I got Strava PBs on some of the climbs without even really trying. It was loads faster, for considerably less perceived effort, on the flat singletrack and climbs. I could accelerate it far better and maintain momentum far better.
I am running considerably higher gearing on the Rockrider as well. 32-32 (2x9) is my lowest gear on that bike compared to 32-42 (1x11) on the Boardman. Despite this, my physical effort on the climbs felt easier and my legs were not running out of steam anywhere near as fast as on the Boardman. On the Boardman I am forced to sit and spin in lowest gear most of the time because my legs are done in trying to push a harder gear on it.
The downside was on the descents where the steeper angle of the Rockrider was noticeable and made it a bit sketchy on some steeper sections of the trail. I dropped the chain as well on a rocky section which never happens on the Boardman.
So Im left with a dilemma now. I enjoy hitting descents fast and securely but i also really enjoyed being able to maintain momentum on the flat and climbs yesterday on the xc bike. The trails I ride are a mix of features. How do I get the best of both?
0
Posts
I thought it may have been a fitness issue hence why i decided to take my old XC bike out yesterday and see what the difference was. In a substantially harder lowest gear I was able to sustain momentum without my legs going to jelly so its not a fitness issue I don't think.
On the Boardman it has a climbing position on the shock which stiffens up the travel. It doesn't have a full lockout on the shock. Other than that I already have the sag and rebound set appropriately.
The full suss is way more comfortable and way more capable on the descents but the draggyness of the climbs and flat singletrack is really frustrating me lately. I just grind to a halt too easily on it, and when I try to push harder my legs go to jelly too easily. This just didn't happen yesterday on the XC bike.
Do I have any options for improving this without sacrificing much downhill capability?
My Rockrider used to have 3x9 gearing it but I dropped the granny ring as never used it. So the lowest gear is 32-32 (ratio of 1). The second lowest gear is a ratio of 32-28 (1.14).
On the Boardman my lowest gear is 32-42 (0.76) and the second lowest gear is 32-36 (0.89) and the third gear is 32-32 (1).
So on paper the Boardman does not seem to have an issue. Why can I push a ratio of 1 to 1.14 on the Rockrider with what felt like relative ease, yet on the Boardman if I go into second cog 0.89 I simply grind to a halt on the climbs? That is what is frustrating me so much. Is it simply the extra 1.5kg? Or is it the suspension sucking up all my pedal power?
I'd think it's both the weight and the suspension that's slowing you down but that's the price for the faster descending.
If not, what bike would offer me better climbing without sacrificing too much on the descents? The Rockrider is an old school XC bike really, what about a modern XC full suss? I could potentially build a bike up from scratch.
I know I probably don't need another bike but the draggyness on the climbs and flats is really frustrating me lately. If I did buy another bike I would have to force myself to alternate between them both to make sure I got the use out of them.
Is it worth replacing the shock for one which has full lockout? Would that make a noticeable difference to climbing or will the weight still be the overriding factor?
The current shock is a Rockshox Monarch RT Debonair 190x51mm. It has a open and a pedal mode which stiffens the shock but does not lock it out completely. The alternative could be the Monarch RT3 which has a full lock as well as pedal and open modes.
Or even a modern XC hardtail now seems to have 68 degree head angles, through axles and 1x12 gearing as well. I'm not sure its a good idea for me to go back to a hardtail though, the trails I ride are very rough.
Or - could I change the rear shock for one which locks out fully? Would that help things noticeably do you think? Or is the weight difference still going to be the overriding factor? The current shock is a Rockshox Monarch RT Debonair, 190-51 size.
If your bikes both had the same gearing, the 27.5" wheeled bike would feel harder to accelerate than the 26er. If the cranks were different lengths, the shorter crank would feel harder.
Then there are the tyres. This has been done to death elsewhere; but wider, stickier and chunkier rubber, and lower tyre pressure will all feel harder to ride uphill.
Rear suspension bob robs you of energy. If the suspension design (like the Horst link for ex) does not minimise this, then pedalling smoothly from a seated position instead of hero heaving up the hill will give great benefits. Shock designers are aware of energy-sucking pedal bob and often add a firm setting that damps out suspension bob. But for me, it is the last resort and I almost never use it.
Ask someone to ride behind you on your FS and watch to see how much your saddle is bobbing up and down and give you a running commentary. Try different things to see if you can minimise bobbing.
Body position is another one to watch. Recently, bikes have been produced with steeper seatpost angles (74-75 deg) that put your weight further forward. This is designed to assist steep technical climbing and shouldn't be a feature on grinding up a smooth slope. But as soon as you bum comes off the saddle, seatpost angle becomes irrelevant anyway.
When climbing technical slopes, the rear suspension comes into its own and will generate contact with the trail more of the time, driving you forward.
The issue for me is the long slog climbs. I've tried to describe the problem but I think its hard to describe properly.
Put simply I really struggle to accelerate the bike and maintain its momentum - and therefore on a climb I rarely get out of 1st gear which is no more than walking pace. It is so energy sapping, that if I try and push 2nd gear or higher, after maybe 10 to 30 seconds my legs have gone and I have to drop back into 1st and spin the rest of the way.
Now I can ride the whole trail this way no problem, but it doesn't feel enjoyable.
On a flat section I also struggle to push above a certain gear as I can feel the energy sapping out of my legs. This means my momentum is not maintained on flat sections either and upon encountering a slight incline I end up dropping gears to prevent stalling, which lowers my pace even more and so on until I eventually end up back in first gear.
As I said above, I thought it might be a fitness issue but upon switching back to my old XC bike, its obvious its not. Not only was I faster on the climbs and flat sections, but that was in a harder gear as well and I felt like I could always push a little harder and get more speed - my legs did not give up on me at all.
What I'm struggling to determine is whether this is down to the weight difference between the bikes, or the geometry, or the suspension sapping up my power.
I notice there is a new breed of bikes out now which didn't really exist before. They seem to have the suspension travel and weight of a lightweight XC bike of yesteryear but with modern geometry, stiffness of components and gearing setups. Eg this one:
https://www.scott-sports.com/gb/en/product/scott-spark-rc-900-team-red-bike
It looks like a really capable XC trail bike cross. Its only 11.5kg (claimed) with 100mm travel but has all the geometry, stiffness, gearing of a trail bike. But its very expensive. A bit like how expensive trail bikes or enduro bikes were a few years ago when they first started getting popular.
I'm not sure what to do. I enjoy riding the Boardman on the descents but I don't enjoy climbing with it. Cannock is hardly very steep either - it won't be fun taking this bike somewhere like Coed-Y-Brenin with its monstrous climbs. I can't really use my Rockrider either - its too old school XC to cope with modern trails - I'll be over the bars on it in no time - my skills on the descents have outgrown that bike now.
Looked up and followed the 109% rule method on YouTube and realised my saddle was too low so raised it by around 40mm felt instantly better. Problem solved.
I wonder if this is contributing to the issue. How can I dial in correct pressure if the sag doesn't appear to change?
Also I had a play about with the two settings (pedal and open). The pedal mode stiffens up the shock but there is still alot of movement there. Bobbing up and down on the bike with just my bodyweight easily produces 30% shock compression even in the pedal mode.
A new shock with a full lockout is easily gonna cost me £200 ish so i'd need to be sure it was going to make a difference before trying it. Plus I'd need to find a shock to fit the older imperial standard which is now redundant.
Im just not happy with how sluggish it is on the climbs and want to improve that.
So I've upped the pressure to 220psi and checked the sag again - still showing 25%.
Then I chucked my backpack on with a 2l water bottle in there to add another 3kg - still showing only slightly higher than 25%, obviously the sag gauge is not too accurate to read off.
So I'm not sure whats going on here but somehow the shock is being sticky and showing around 25% sag no matter what the actual pressure is.
Also I noticed there is still a good 20% movement on the shock when in pedal mode.
The way the bike feels on the climbs - with it feeling so energy sapping if I try and push hard - it could well be the suspension sucking up all my pedalling effort. If for some reason that sag measurement is not right and my pressure of 170psi was far too low, then that could be the reason. I'll need to ride it at 220psi now and see how it feels.
As noted above, your FS is 27.5 and your RR 26" wheel, so just for that you need to multiply the gearing on the FS by 27/26 (a 27.5 wheel is 27" on the same determination that makes a 26") or add 0.04 (as a rule of thumb on ratios around 1). Plus if you have wider (larger rolling radius) tyres you have to factor that in as well.
I like strong pedal support for climbing, when I first rode my T129 it had a basic Monarch on and climbing was a chore, I now have an RP23 which is much much better. I came from a very lightweight (sub 10kg) XC FS bike with a fifth element shock which also had a strong platform. Sitting and spinning effectively means circa 90rpm, not many riders 60rpm.
From the specs a Pro has a Monarch RT, so you have a single threshold (pedal platform) setting, there should be a small sticker on the shock telling you which of hard/med/soft (from he stock offerings) Boardman specified for your bike.
The current shock is a Monarch RT debonair 190x51 fitting size. The sticker on the shock says:
-M
-then a little open padlock symbol with L3 on it
-then a dash (-) symbol
-then a closed padlock with the numbers 320 underneath
L3 (low3) is the unlocked compression damping
320 is the lockout compression damping.
From what I can find 320 is the 'soft' pedal platform, 430 is the stiffer one available for the RT although a specialist like TF tuned could possibly have other settings available.
Not sure what you mean by 'full lockout', shocks don't have that, they have the pedal platform/low speed damping, you could try one with an adjustable threshold like the RP23 or Monarch RT3.
A volume spacer in the air can will also tend to give you better support by increasing the spring rate progression.
https://www.sram.com/en/rockshox/models/rs-mnr-rt3-d2
There is also a specific way to inflate your shock. You can no longer just pump it up and go! See page 19. Observe the graphics on 19 and 20
https://www.servicearchive.sram.com/sites/default/files/techdocs/95.4118.001.000_user_manual_rear_suspension_rev_b.pdf
Once you are sure that your shock has been inflated correctly, then there are the tuning guides to follow. By all means do what Rockshox tell you, as it's a great place to start. But if you have an interest in suspension tuning in general, I can 100% recommend the following guide from Bike Rumour. Download and store.
https://bikerumor.com/2014/10/30/bikerumor-suspension-setup-series-full-series-pdf-free-download/
I can only see 430 available in the RL variant of the Monarch which has two modes - open and 'full' lockout - no pedal mode?
I've tried searching for the Fox RP23 but can find none for sale new.
@steve_sordy thanks for the guides. I already cycle the shock when im pumping it up but I was paying attention to the sag not the pressure. That tuning guide looks good i'll take a proper look at it.