Bigger rear disc = less skiddy?

I’ve been struggling recently riding some steeper trails. Particularly loose, steep stuff. I find the rear wheel locks up too easily and I just skid and slither my way down in a sideways fashion. Sometimes fun but also terrifying on occasion, depending on the consequence of going over the edge of something. I’m talking steep stuff with corners or awkward bits that mean you need to be going slow.

Anyway, I’m wondering if a larger rear disc offers better or worse modulation? I know increasing the disc size equals the feeling of more power (or needing less lever effort to achieve the same power) but is it easier to modulate?

Despite the so called grabby nature of Shimano, I find the brakes generally ok. I’m fairly delecate on the levers and even feathering the brakes and balancing things out by increasing the effort on the front, the rear seems to go from nothing to locked up on steep stuff.

Brakes are Deore M6120 with a 180mm XT Icetech disc on the back.

Is a grippier tyre a viable option here?

If you’re pulling less hard, you’re more likely to be able to modulate.

More front brake possible? Should mean slightly less rear and less skidding…suspect a larger rotor will make skidding more likely, so probably needs less pull on lever.
Your last paragraph suggests the brakes are very grabby – nothing to skidding, if there is no in between it pretty much is grabby – which isn’t helping with your issue, sorry.

Smaller rear wheel?

[ insert appropriate Unicode Emoji here ]

Smaller rear wheel?

Will it make the trails come more alive?

I’d expect it to be more skiddy not less.

Grippier tyre design, softer rubber, lower pressure, different brakes.

“the rear seems to go from nothing to locked up on steep stuff.”

Isn’t that just the nature of steep loose trails? There’s so little weight on the rear tyre when a bike is tipped forward that much.

It’s complicated, a bigger disc all other things being equal will lock up more easily, but what matters more is how it affects you- will you get less fatigue, will it be just in a happy point where you have the best control, will it feel just right? Or, not.

TBH I’d be thinking about tyres too. Not necessarily grippier (though, maybe) but also how it slides. It’s why the DHR2 is such a bloody brilliant rear tyre, it’s got decent grip but mostly it’s really managable when it lets go, tends to go where you expect it to, isn’t too abrupt, and getting it back is easier than most. Whereas there are other tyres like, say, the Dissector, that grip OK but slide terribly, just really wild and unpredictable and unmanagable by comparison.

Anyway, I’m wondering if a larger rear disc offers better or worse modulation?

Worse modulation, more power.

But you need a grippier tyre (and a suspension bike if you’re riding a hardtail.)

As a coach we teach riders to really ease off the back brake on steep stuff specifically because of what you describe. I’d start with technique before thinking about changing parts on your bike.

If you’re really relying on your back brake a lot there’s some good drills you can do to improve confidence with the front brake (I’ve had to do this myself). One is to ride a (not too steep!) track you know really well and use only your front brake.

This is a reasonably good read (about braking for corners, but it helps improve confidence with the front brake):

The Ultimate MTB Cornering Drill (betterride.net) 

I’m with Reeksy on this. Steep downs will put more of your weight forward, unloading the rear. This will reduce grip so to avoid locking the wheel and skidding you’ll need to reduce your rear braking.

You’re not in Calderdale by any chance are you? These days the place is full of the trails you describe.

Anyhow, the secret by all accounts is more weight on the front, something I struggle with past a certain point of steep/loose/slick. Oh, and being able to endo turn, because if you can’t, you ain’t getting down them and are now somersaulting through space!

It is truly amazing to watch those that can though.

It is entirely possible of course that I’m just riding stuff which exceeds my abilities. I do look at some steep stuff and can’t quite wrap my head around how on earth your actually supposed to ride it.

Tyre wise, I’ve swapped between a Dissector, an XR4 and an SE5 recently. All at fairly low pressure. Front is an SE6 which I’ve become very fond of. Generally, the front digs in nicely even on super steep and slow bits.

On occasion, the front loses grip on (what I would consider) super steep and slow bits but that’s because I’m getting so far off the back to find rear grip that the front end isn’t getting enough weight. I run the fork fairly supportive to try and keep the front end up.

I guess this has turned into more of ‘how do I ride down steep stuff’ question rather that anything to do with braking lol

I have been thinking of trying some different brakes but it ends up being quite expensive for something I may not like!

SOoo

my Top fuel is on Xr4’s, i also have had to stop riding it and ride the big bike on the dry steep stuff, the top fuel has a low front end also which i fear added to the drama. however, my bigger bike which has a fresh HR2(previously a worn dhr2) gives much more confidence on the same surfaces. I’m eager to try the Trek on a 130mm fork to bring the front up a bit to see if that helps with the weighting.

But basically.. the Xr4 rear in my example didn’t work for steep dusty switchbacks for me and put the fear of god in me, BUT in literally any other riding scenario it is superb, leading me to think weighting was part of the issue

Get a DHR11 on there to discount it just being a skippy tyre.

I did have a DHR on there. The Rekon that came fitted to the bike basically tried killing me at every opportunity so I fitted a DHR and rode it for a while. It worked well but it was a bit too draggy for all day rides which is when I went off in search of something lighter and faster.

Putting it back on and finding something steep to test it on is probably a good idea tbh

 It worked well but it was a bit too draggy for all day rides which is when I went off in search of something lighter and faster.

Tyres are always a compromise. If you want fast rolling, you’ll compromise grip. If you want grip, you won’t get fast rolling. Changing your brakes won’t make your rear tyre grip better. A bike you can ride all day will be a compromise that will sacrifice DH grip. A bike that can handle the toughest descents will sacrifice all day pedalling.

the other thing to consider is rear tyre pressure – as you’re unloading the rear the inches touching the ground reduce. Lower pressure will help with that. How much have you got in there?

Currently, I’ve got the SE5 (2.5″) on there at 19psi. That’s just about on the limit I reckon. Had a couple of fairly a abrupt, dull thuds the other day which I assume was the rim was doing unsavoury things to the sidewalls courtesy of some particularly prominent rocks.

Generally, I’m fairly kind to wheels so I could maybe drop a bit but I prefer to keep a little bit of a buffer.

How about an aggressive knobbed tyre in a harder compound?

Kryptotal Re Trail/Endurance rolls way faster than a Dissector MaxxTerra yet has a lot more bite.

I noticed a better feel at the lever when I went from 180mm rear to 220mm, better bite and a greater sense of modulation which worked for me on the steeps as I could be more be precise with doing on and off instead of on and dragging.

Its a relatively cheap upgrade too, so just give it a go!

I am Kryptotal curious. Have been for a while now because I really want to see if they’re as good as everyone says they are.

Having considered the skiddy thing on the last couple of rides, I’m fairly sure that the tyre is part of the issue. The SE5 works really well on most things but definitely lacks traction on wet rocks etc. I’ve convinced myself that I want a softer compound. I raided the tyre pile and found a Maxxgrip DHR so I’ll whack that on and see what happens. Whatever happens, it’ll happen slowly from what I remember.

As much as I’d love to put all of the blame on things that aren’t me, I’m fairly sure it’s at least partly a technique thing. I found a trail over the weekend that’s a perfect example of the type of thing I struggle on. Steep, loamy, loose with awkward corners and tiny little catch berms. I think basically im scared of the bike running away on the steep stuff and accelerating to the point where I can’t slow down for the corner or whatever is coming.

If I was confident enough to take steep corners at speed, I’d probably be fine but I think I’m trying to control my speed too much on the way in and dragging the brakes which just makes the back end skid down the hill.

I did try and fit a 203mm disc but there wasn’t enough slack in the hose to bolt the caliper up to the adaptor. I might be able to wiggle a bit more through the frame but it’s hard up against the battery and I’m not sure I have the enthusiasm to drop the motor to investigate.

I’m using Kryptotals at both ends on my Rail. I’m 106 kg at the moment 1.92m tall. I’m big! Riding a large bike.

Today’s fun and games was blasting around Coed y Brenin, followed by some madness in Cwm Penmachno quarry, the incline that is the missing link on the Traws Eryri route. Tyres, bike and technique all worked fine in CyB. Riding up the incline, loads of grip at both ends but I veered off to the side about halfway up and just couldn’t get going again.

Descending the incline was a hoot. It’s dead straight, damp grass with a bit of rock sticking out here and there. It took a proper combination of body position and braking control front and rear to stay on line. Too far forward and the rear would gradually start to slip, too far back and I felt that the front was a bit unweighted but the front never gave me any reason to worry at all.

I was barely braking at back at times for fear of loosing it, but so long as the rear was rolling and not locked up everything was rosy.

On the mega fast loose slate covered incline lower down the tyres were faultless.