Is it my tyres.....

paul.skibum

Hi All

Havent posted on here in a while.

Just got a new Nukeproof Scout hardtail - I like.....BUT...it feels like I am dragging it through mud compared to my old hardtail or my 5010. Winter drew to an end and the bike arrived - first few rides I was feeling slow and my legs like lead and I put it down to post snow covered trail hibernation despite time on a turbo trainer recently.

This weekend I took my 5010 out for a spin and it felt like a rocket - acceleration and power - my legs felt good on a decent length ride and still had some oomph at the end of the ride. Comparatively the Scout feels slow and hard work at every pedal crank.

Similar gearing on both bikes the only difference I can conceive is the 2.6 tyres on the Scout vs the 2.35 on the 5010 (also tubed vs tubeless) - can it simply be the tyres?

Could I be getting drag in the system somewhere (cranks were fitted when I got it - maybe over tight?) I am planning to swap wheels on the two and try the tubeless 2.35s on the Scout but have no experience with 2.6s before now so wondering if anyone else had any ideas! The 2.6s have a TONNE of grip so I'd like to keep them but cant stand the drag!

figbat

What tyre pressures?
Seat height the same?
Brakes dragging? Do the wheels spin freely?

I recently had an issue with feeling like I had lost two years of fitness riding the same bike over the same trails. It turns out the new seat post clamp I had fitted was not quite tight enough and the saddle was slowly dropping. I put it back and enjoyed my newly refound fitness.

paul.skibum

Saddle height is good, no brake drag, tyres pumped up pretty much the same (I dont do pressures but both feel similar - Scouts probably a bit firmer), wheels spin freely.

I am going to chuck it on the stand again tonight and have a play around and try different wheels - just wanted to ask the question!

tom_howard

what tyres are you running on each bike. Tread pattern makes a massive difference, as does weight, sidewall construction, profile etc. same with wheels

billycool

What weight is the bike?
What weight are the different wheels?
Tyre pressures can have a massive impact on tyre contact/drag
More grip = more tyre contact = potentially more drag

Not that simple but you need to understand the impact of the variables. Swapping wheels over is a good idea.

Try a higher pressure in the 2.6 as well.

steve_sordy

Is it possible to swap the wheels over?

The Rookie

Do a no pedal roll down the same hill and compare times and speeds on strava (other GPS based datalogging is available) between the bikes.

And get a pressure gauge!

paul.skibum

Jesus you guys and your details.

Both bikes are running DHR2 and DHF - one is 2.35 and one is 2.6 - the 2.35 is at around 26psi per my dodgy Park tools pump (has a ridiculously shit gauge on it for a Park tools device). The 2.6 are at about 30psi.

Both bikes weigh about the same - the Scout is surprisingly light for a well built alloy hardtail, the 5010 is a relatively light carbon trail bike. Dont have exact weights for either because....I dont really care.

I have ridden both bikes on the same section of tarmac valley trail and the 5010 I can stick in the 10t and crank along out of the saddle with ease, the Scout I am in 13t and sat labouring away, out of the saddle sprints are exhausting in short order. The hardtail to me should be all zip and fire where the FS should be sucking power from me with the suspension and that is my experience with my old hardtail.

I can swap the wheels between bikes and plan to do that - my herniated back will not thank me for a hardtail on 2.35 tyres though! I also plan to try the Scout tubeless in due course. It is currently in the shop for a brake bleed as the front brake came spongy.

Mechanic at LBS mentioned that the Mavic XA wheels can be draggy for a few rides - not found much on the MTB wheels but lots of mentions of that issue for their road bike XA wheels.....

robertpb

The 2.6 tyres need to be 2-3psi lower than the 2.35's. Also the combo of the wider tyre and presumably wider rims on the Scout will be heavier so the feeling of more drag.
Another point to make is check the relationship between the front of the saddle and the bottom bracket on both bikes, you may be sitting in a different place to the cranks on each bike, can make a difference to the amount of power you are putting into the cranks.

paul.skibum

robertpb wrote:

The 2.6 tyres need to be 2-3psi lower than the 2.35's. Also the combo of the wider tyre and presumably wider rims on the Scout will be heavier so the feeling of more drag.
Another point to make is check the relationship between the front of the saddle and the bottom bracket on both bikes, you may be sitting in a different place to the cranks on each bike, can make a difference to the amount of power you are putting into the cranks.

The seatpost is definitely steeper on the Scout and the pedalling position a little more over the cranks which does seem to move the muscular effort a little.

And yes the rims are wider on the scout - I didnt weigh the wheels to compare but could do that to see what the difference between them is. Why would I want the wider tyres at a lower pressure - would that not increase the contact patch and increase the drag?

swod1

I think someone has mentioned it before but could also be the wheel bearings being new and once a few rides in might loosen up.

Did notice that with my hope bottom bracket on my bike seems fine now.

Maybe make the scout into a xc light trail bike with faster rolling tyres?

steve_sordy

paul.skibum wrote:

robertpb wrote:

................

Why would I want the wider tyres at a lower pressure - would that not increase the contact patch and increase the drag?

The area of the contact patch is proportional to the weight of you and your bike divided by your tyre pressure. For a given width, the shape of it is affected by your wheel diameter. The larger the wheel diameter the longer it is. It changes as you move about the bike and with the amount of bouncing about you do, but pretty much I'll stick with my first two sentences.

If you have two wheels with the same tyre pressure and one wheel has a 2.8" tyre vs another at 2.4, then unsurprisingly both will have the same contact patch. (Weight divided by pressure = area). But the wider tyre will have a shorter contact patch, because it is wider. This shorter contact patch make the tyre feel harder and more springy, less damped if you like. Once I have found a tyre pressure that works for me, when I come to using a tyre that is narrower or wider than what I have been using, then my starting point would be to change the tyre pressure in inverse proportion to the change. So if I was happy with 30psi on a 2.4" tyre and was moving to a 2.8" tyre, I would start with 2.4/2.8 x 30 = 26 psi. That would be only the starting point. I would ride the bike and then see how it felt before making further changes. There are many things that affect how a tyre feels apart from width, diameter and pressure: tread pattern, composition, carcass design and strength, tubeless or not... to mention a few of the more obvious ones.

People often forget that tyres are the first layer of suspension. High pressures work fine when the trails are smooth as they lower rolling resistance (look at road bikes). But once the trail roughens up a bit, the hard tyre starts to bounce back and slow you down. Reducing the pressure allows the tyre to conform to the rough bits without kickback. As a consequence, the bike flows more smoothly over the trail and you go faster! Getting the balance right is a process of adjustment, but it is key to getting the best out of your bike. Go too low, and the tyre squirms underneath you on corners and may even come off the rim.

I have ridden down rooty trails without pedalling and my mate behind me has had to pedal to keep up. The only significant difference in our set up at that time was tyre pressure. See this excellent video from Pink Bike's Tech Tuesday series on how to get the right tyre pressure.
https://www.pinkbike.com/news/Tech-Tues ... -2011.html

paul.skibum

steve_sordy wrote:

paul.skibum wrote:

robertpb wrote:

................

Why would I want the wider tyres at a lower pressure - would that not increase the contact patch and increase the drag?

Stuff

I cut out the whole quote as it was quite long.

Interesting answer but the tyre pressure issue is also a red herring to my actual problem as low or high pressure is not going to make the tyre feel draggy (in fact higher pressure is likely to give me less feeling of drag esp on tarmac vs less pressure).

Bike will be back from shop today (if I can get there to pick it up) so I will have to have a play with changing wheels between bikes and maybe even putting a spare ardent I have on it.

paul.skibum

So turns out it wasnt entirely my tyres - I may have screwed up while putting the bike together and added a bit of drag to the system......Tyres are definitely still slow vs my other bike but not as much as I was initially feeling!

I need a better lit garage and bike stand I think!

mattyfez

What tyres are you running on both bikes? And what pressures?

As said above that can make a huge difference.

Simply saying 'I don't do pressures but they feel similar' I'm thinking is the crux of the problem here.

billycool

paul.skibum wrote:

So turns out it wasnt entirely my tyres - I may have screwed up while putting the bike together and added a bit of drag to the system......Tyres are definitely still slow vs my other bike but not as much as I was initially feeling!

I need a better lit garage and bike stand I think!

I think you might need to explain.... :?

yonny

paul.skibum wrote:

Both bikes are running DHR2 and DHF - one is 2.35 and one is 2.6 - the 2.35 is at around 26psi per my dodgy Park tools pump (has a ridiculously shoot gauge on it for a Park tools device). The 2.6 are at about 30psi.

Both bikes weigh about the same - the Scout is surprisingly light for a well built alloy hardtail, the 5010 is a relatively light carbon trail bike. Dont have exact weights for either because....I dont really care.

My brother had the same tyre combo (2.6) on his Remedy 8 and switched down to 2.35 (what I run) to keep up with my Carbon Stumpjumper. It made a huge difference but he was still a little behind. He ended up getting the carbon Remedy frameset and switching all the components straight over. It did the job, it's a much quicker bike now. Weight difference between the ali and the carbon is minimal so it has to be something to do with how the stiffness transfers the power and weight distribution into speed.

paul.skibum

BillyCool wrote:

paul.skibum wrote:

So turns out it wasnt entirely my tyres - I may have screwed up while putting the bike together and added a bit of drag to the system......Tyres are definitely still slow vs my other bike but not as much as I was initially feeling!

I need a better lit garage and bike stand I think!

I think you might need to explain.... :?

chain routing issue at the mech - dragging on the plate between the jockey wheels - I didn't actually think it was possible to fit it wrong and even if it was I am surprised it wasnt making any noise to let me know. Stupid error is stupid.

Update - fiddled with pressures a mite, not too much, rode a 20k loop with 650m climbing on Monday, rode a black route down in Pemby - love it! 2.6 tyres give so much grip and bump over ability, loose and dusty trails where I would have lost grip totally on my 5010 I was in complete control. Definitely a mite harder pedalling than the other bike but for the grip I cant fault them.

kirkymtb

I have bikes with 27.5" and 26" Continental Trail Kings, both 2.25 wide. OK I tend to run the 27.5s at lower pressure but I can definitely feel more drag. This is backed up by Strava. Is the 26" wheel the answer?
No, not really! The 26ers are more skippy on bumpy trails, leading, occasionally to slides where the bigger wheel would have gripped. It's 'orses for courses. I had set a KOM on my 27.5 but beat it on my 26. It has a few corners but is a pedally downhill. I'm not trying to prove anything. I just find the whole tyre diameter and width thing fascinating. I don't think we've found Nirvana yet.

billycool

KirkyMTB wrote:

I have bikes with 27.5" and 26" Continental Trail Kings, both 2.25 wide. OK I tend to run the 27.5s at lower pressure but I can definitely feel more drag. This is backed up by Strava. Is the 26" wheel the answer?
No, not really! The 26ers are more skippy on bumpy trails, leading, occasionally to slides where the bigger wheel would have gripped. It's 'orses for courses. I had set a KOM on my 27.5 but beat it on my 26. It has a few corners but is a pedally downhill. I'm not trying to prove anything. I just find the whole tyre diameter and width thing fascinating. I don't think we've found Nirvana yet.

I'm much the same. Still ride HT and FS in 26". Rode Afan (South Wales) at the weekend. Plenty of climbing (not my favourite subject) and some really nice flowing and slightly sketchy downhill stuff (more my thing).

I kept up with friends on `quicker` 27.5 and 29" wheels.

The main difference was that we were on quite technical stuff and my 26" wheels like that (as do I). I'm also happier riding like that. On the flatter stuff (and climbing) they did better than me. It's all horses for courses and also rider fitness/ability. Wheel size is not the be all and end all.

I have the TK's on my FS bike and love them. Tend to run them a bit high 30-35psi, but that suits me. On Sunday we rode Blue Scar before our trip home and I didn't notice that my rear tyre had lost some air. Rode it on about 25 psi and on the downhill it squirmed really badly and wasn't much fun.

I still have some Strava KOM's local to me, as I have bigger b*lls and smaller wheels!

mattyfez

We don't know what pressure he's running or what style tyres he's got...

It's pretty pointless trying explain further than that.

paul.skibum

mattyfez wrote:

We don't know what pressure he's running or what style tyres he's got...

It's pretty pointless trying explain further than that.

I am pretty sure I mentioned the pressures, thought I mentioned the tyres too - both bikes have DHF and DHR2 front and rear respectively - so broadly the same tread patterns but 2.6 vs 2.35.

So on further rides and inspection I can confirm that "snappy" acceleration is not a thing with the 2.6s - there is a lag and weight to it that robs me slightly of that playful burst of acceleration I love a hardtail for but it grips for its country in grippy world champs and corners well - I find the steering a little wayward on tight stuff but I think that is down to the stem/bar combo on the bike and I may need to play with that to get more out of it.

The 2.35s on the 5010 offer the snap of acceleration where oddly last summer (riding my old 26er HT) I would have said the 5010 was the less snappy bike. its quick and direct vs the plough of the new HT.

The question I raised actually stemmed from an unspotted error in chain routing causing me more drag in the drivetrain than there should have been but having sorted that I am still left with the same feel. I like the new bike its a great ride and I'd consider going to just a hardtail in this set up if my back was a bit more able to cope with that.

JBA

paul.skibum wrote:

mattyfez wrote:

We don't know what pressure he's running or what style tyres he's got...

It's pretty pointless trying explain further than that.

I am pretty sure I mentioned the pressures, thought I mentioned the tyres too

You did, paul.skibum.