Gravelising rigid MTB – wheels, tyres, mudguards

Bought myself a rigid Kona Unit X for short commuting and evening rides from the door duties, didn’t want a gravel bike. So the terrain is a bit of tarmac, lot of cycletrack (tarmac or fine gravel old railway lines), and a few tame bridleways and farm tracks.

The wheels and tyres it came on aren’t the right ones for the purpose I have. WTB Ranger TCS Light Fast Rolling 2.6″ (1013g each) on WTB i30 ST / Shimano MT400 (2255g). I’ve been surprised by the comfort they offer on broken and rooty tarmac though, my only previous rigid experience being an old 24″ bike on 1.95″ tyres. Previously I was expecting that I’d need to fit a suspension fork. So ideally I could keep some of that comfort but still be better rolling, although I’m open to putting a Reba fork on it if needs be.

Thinking of putting some of the fastest rolling XC tyres I can find on it, namely Continental Cross King front and Race King rear in 2.3″/2.2″. They test well on bicyclerollingresistance.com and are 400/250g lighter each. Earlier I was looking at gravel tyres and found the Schwalbe G-One Bite/Ultrabite, but according to the tests on that site they somehow roll slower than those Contis despite the version tested being narrower, lighter, and less aggressive tread. Also looked at the extensive Schwalbe city/tour range, nothing here looked any good for off-road or good rolling. A few people did once say for comfort, keep the volume but lose the knobs. What kind of tyre, or any specific ones, should I be looking at?

The rims are a tad wide for the XC tyres but should be fine according to the WTB compatibility chart. They are heavy though, and the hubs are loose bearing. Hunt or Silt XC 25mm 28 spoke ones are possible options to swap, not sure if it’d be much noticeable though?

Should be able to get full mudguards to fit whatever I come up with. Looks like it has to be SKS Bluemels 65/75 if I go for XC tyres; the AL 56 is for 2″/50mm max, the PDW 55mm is for 47mm max, and the Velo Orange 63mm is for 2.1″/55mm max. Lots of positive comments here on the latter ones compared to Bluemels, but they just wouldn’t fit.

I have Specialized Crossroads 26 x 1.9 on my Charge Duster geared town bike. They have a smoothish centre section and some knobbly sides. Not as easy on the road as the ones on my carbon Pinarello, not as grippy off road as the tyres on my Giant Trance but they’re just right for what I have them for.

Interested in the tyre options that come up here. I used Vittoria Terreno 2.25s for a week of lanes, the Trans Cambrian Way and more lanes and stony mountain tracks in Wales this summer. In mainly dry (for Wales) conditions they were impressive – fast, smooth and generally grippier than I expected. Very quick on road. Better than the Conti Speed Kings I’d used before as they had a more useful cornering edge. I prioritised a smooth centre tread to eliminate vibration on tarmac but I’m after something similar with more tread, if it exists. A moon-on-stick tyre for average/wetter conditions and general off-road use with that smoother road feel.

There are some good ‘SUV’ tyres coming out for E-MTBs that spend a lot of time on tarmac eg the Conti Ruban. Close centre treads with decent side knobs. But they’re all burly casings for e-bike use.

keep the volume but lose the knobs

Most brands list the tyre width as the outside edge-to-edge dist so a smoother tyre often has a larger volume casing than an equivalent labelled size treaded tyre.

For guards, try to get something that uses external loop stays. Internal stay fittings eg SKS types are a PITA off-road as they snag a lot more debris and clog faster.

I’ve got WTB Nine Lines on my monster gravel bike which is essentially a drop bar mountain bike. Nicely fast rolling and as long as you get the tyre pressure in the right zone (high enough to roll quick, low enough to provide some cushioning) they’re great.

Those wheels will be chonky.

First stop is replace them with some XC hoops and 2in tyres as you suggest.

And consider do you really need full, fixed guards or could Mudhuugger-style guards do you?

Full guards will keep spray off you much better, but if clearance is at all tight you may find stuff is constantly getting jammed between tyre & guards.

I’m commuting on my old Diamond Back MTB (90’s). Full guards and I can get upto 2.0″ tyres under the guards. Currently using Schwalbe Landcruisers – good enough for off road, as well as a central ridge to help rolling on tarmac.

Vittoria Terreno 2.25s

Shame they don’t do multiple variants of the MTB ones like they do with the gravel ones, which top out around 40mm.

There are some good ‘SUV’ tyres coming out for E-MTBs that spend a lot of time on tarmac eg the Conti Ruban. Close centre treads with decent side knobs. But they’re all burly casings for e-bike use.

Does look like more tyre than I need. They need to update their old traffic/town&country ones, make them in sizes other than 26, and perhaps have a separate eMTB version to avoid compromise.

For guards, try to get something that uses external loop stays. Internal stay fittings eg SKS types are a PITA off-road as they snag a lot more debris and clog faster.

That constraint leaves only Velo Orange 63mm as an option, and with it a max 2.1″/55mm tyre.

I’ve got WTB Nine Lines on my monster gravel bike which is essentially a drop bar mountain bike. Nicely fast rolling and as long as you get the tyre pressure in the right zone (high enough to roll quick, low enough to provide some cushioning) they’re great.

Seen a few people mention these, but haven’t found any comparisons mentioned or proper reviews/data. Good to hear you have comfort with this size tyre on a rigid.

Was also looking at Racing Ralph, Racing Ray, Rocket Ron, and Thunder Burt. Didn’t see anything in them over the Contis, bit more racey, and don’t score as well on the rolling test.

No gravel tyre suggestions so far, so is fast XC tyre the way to go?

You’re describing my bike. Currently waiting on a Calderdale train station platform having knocked out a high loop of lanes, bridleways and canal path. Old Kona Lava Dome frame with sliding dropouts like yours; SKS Bluemels; Land Cruiser Plus tyre on the front, Big Betty on the back. These are much better for me than the G One Bites they replaced, which gripped and rolled well enough but were too puncture prone.

And consider do you really need full, fixed guards or could Mudhuugger-style guards do you?

Full guards will keep spray off you much better, but if clearance is at all tight you may find stuff is constantly getting jammed between tyre & guards.

Will put a rack on the rear for commuting/town duties, so Mudhugger won’t do. Also part of the reason for this bike is doing short evening rides without a big overhead of washing bikes and clothes. Plenty of clearance on the bike, just means I have to compromise and go for Bluemels as the good tyre options are just a bit over the max for Velo Orange.

I did look a bit at the internal vs. external full loop stays of the different guards, and what jameso said above. The SKS safety release thing seems like a good idea, but as mentioned is something that could aid clogging. Some horror stories on here about jammed guards. No claggy mud here, but sticks and stones yes.

Land Cruiser Plus tyre on the front, Big Betty on the back. These are much better for me than the G One Bites they replaced, which gripped and rolled well enough but were too puncture prone.

Thanks. I was indeed concerned about abusing gravel tyres too much.

https://www.schwalbe.com/en/tour-reader/land-cruiser-plus
2/6 score for rolling
1180g in 2.15″ 29″
What’s the attraction other than puncture protection?

Shame they don’t do multiple variants of the MTB ones like they do with the gravel ones, which top out around 40mm.

There’s a few isn’t there – I have the Terreno Dry G2 TNT spec

That constraint leaves only Velo Orange 63mm as an option, and with it a max 2.1″/55mm tyre.

If you can be bothered you can buy the stays and fixing parts separately from VO and fit to a wider plastic guard, that’s how I got the guard spec I wanted on my gravel bike. I find you only need a guard 5mm wider than the tyre as long as you have enough room between them. A bit wider is better but +5mm can work if the guard isn’t too small a radius x-section.

There’s a few isn’t there – I have the Terreno Dry G2 TNT spec

Given you have 2.25″ it must be the MTB one which is just “Terreno” ? https://www.vittoria.com/ww/en/tyres/gravel-cross https://www.vittoria.com/ww/en/tyres/mtb-xc

I find you only need a guard 5mm wider than the tyre as long as you have enough room between them. A bit wider is better but +5mm can work if the guard isn’t too small a radius x-section.

Actually looking in millimetres, the Velo Orange 63 would be ok on the recommended limit of the 2.2″/55mm tyres, and by your tip maybe a 2.3″/58mm for the front.

So do I want internal stays potentially prone to snagging debris, but with safety release (SKS), or external loops which have a higher chance of sending me OTB if something gets stuck in them? Plenty of people getting on fine with Bluemels but there’s quite a few bad comments about them, I guess it depends on what terrain they’re being used on.

the terrain is a bit of tarmac, lot of cycletrack (tarmac or fine gravel old railway lines), and a few tame bridleways and farm tracks.

For that sort of use if you’d be happy with <50mm tyre width, the SKS  AL56s you mention are ideal. It’s not just the width but also how rigid they are hooning along offroad: no rattles or hitting the tyres etc like I go with narrower tyres and chromoplastics. I’ve got AL56s with Clement X’plor mso 700x50s (not readily available now) and reckon my use is more offroady than the descrition of yours. I never take my guards off – the point you make re avoiding the big overheads of laundry/cleaning on short rides is a big reason I set my bike up the way I have, although it’s also my commuter.

I looked at wider full length guards to allow wider tyres but nothing was reviewed as being as rigid as the AL56s.

And wheels. I built Pro4s with DT Swiss xr391s and saved a chunk of weight, set up tubelessly – quite noticeable. I was tempted by the lighter xr361s but 391s keep options open for wider tyres in future.

 Bluemels but there’s quite a few bad comments about them,

I had Blumels combined with Maxxis Icon 29×2.2 and Tread Lite 29×2.1. One word: crap. Too flexible for even mild manicured tame trail centre use, they just weren’t rigid enough to avoid contact with the tyres over the slightest bit of nobbly ground.

Very dependent on the terrain they’re being used on, as you say. This is the sort of trail they were crap on – too much rattling around:

Pair of mezcals in 2.1 or 2.25 will give you cushion and low rolling resistance and can cope with dry MTB trails as well as gravel. Surprisingly ok in mud too at lower pressures. Got them on the drop bar MTB in 29″

Teraval 47mm cannonballs cope with a bit of…ahem…damp too

What’s the attraction other than puncture protection?

In the 650b size I’m running they were cheap enough to take a punt on and find that, in the real world, they worked fine for my needs.

My Bluemels are pretty solid but I was careful setting them up. Extra mount put though securing the rear to the seatstay bridge, and a fender flute at the front.

Given you have 2.25″ it must be the MTB one which is just “Terreno” ?

Seems so – this one
https://off.road.cc/content/review/2021-vittoria-terreno-review-8391
in the gravel range the same pattern is called Terreno Dry

Mezcals were an option I considerd, I’d done a lot of miles on Geax Saguaros which were very similar and they’re great on dry to soft off-road stuff but the mild buzz from the tread got on my wick a bit on longer stretches of tarmac. That’s me being fussy though, good tyres generally.

RE Blumels

Too flexible for even mild manicured tame trail centre use, they just weren’t rigid enough to avoid contact with the tyres over the slightest bit of nobbly ground.

I found the front attachment, the SKS security clip, was the main problem. It doesn’t let you get a very rigid triangulation of the guard to the fork. They flexed side to side a lot and the stays buzzed the tyre. Maybe if there’s enough length to remove the Seccu clip and mount the stay direct they’d be more stable (but risks jamming).
The trad stays that VO and Honjo let you get a very stable fitting. Aluminium guards even more so but I won’t use them off-road, if anything jams I want the guard to break not fold up under the crown.

or external loops which have a higher chance of sending me OTB if something gets stuck in them?

Not if you use these clips to fix the stays. Anything jamming a front guard can be risky but these can be set up rigidly while being able to release if there’s a pull on them –

For that sort of use if you’d be happy with <50mm tyre width, the SKS AL56s you mention are ideal. It’s not just the width but also how rigid they are hooning along offroad: no rattles or hitting the tyres etc like I go with narrower tyres and chromoplastics.

50mm would probably be fine, but I haven’t found such a MTB tyre. Only gravel ones which are less durable.

I had Blumels combined with Maxxis Icon 29×2.2 and Tread Lite 29×2.1. One word: crap. Too flexible for even mild manicured tame trail centre use, they just weren’t rigid enough to avoid contact with the tyres over the slightest bit of nobbly ground.

Bluemels are now out of the running, thanks.

Pair of mezcals in 2.1 or 2.25 will give you cushion and low rolling resistance and can cope with dry MTB trails as well as gravel. Surprisingly ok in mud too at lower pressures.

Might be an option for the front instead of a Cross King (29W), but it’s a bit more draggy (28W) than the Race King (20W) for the rear.

Not if you use these clips to fix the stays. Anything jamming a front guard can be risky but these can be set up rigidly while being able to release if there’s a pull on them –

Oh, those are just like the standard R clips that Velo Orange use.

Alternatively, or perhaps as an improvement mod, https://ridepdw.com/collections/fenders/products/full-metal-fenders-safety-tabs

They test well on bicyclerollingresistance.com and are 400/250g lighter each. Earlier I was looking at gravel tyres and found the Schwalbe G-One Bite/Ultrabite, but according to the tests on that site they somehow roll slower than those Contis despite the version tested being narrower, lighter, and less aggressive tread

Looking at the results it seems there’s a good reason for that. The tests are run at set pressures not relative ones. So high pressure for the g1 is the same as high pressure for the race King protection despite it being 75% and 95% of the recommended pressure respectively.

The site looks to be numbers for the sake of numbers and little actual applicable science.

So I think my mistake appears to have been comparing results between the MTB and gravel datasets.

IME there’s not much worse in the cycling world than getting a puncture during a commute, or finding a flat at either end of a commute, especially at home time.

A few years back I had a pair of 2.35″ G One Speeds on my 29ered fatbike, they were super speedy, but I then had two or three punctures in a couple of weeks.

The 50mm Marathon Supremes (I now use the 35/40mm variants) seem to be OOS at Merlin, but https://www.merlincycles.com/schwalbe-marathon-plus-smartguard-wired-mtb-tyre-29-163167.html for at least for the rear might be worth piece of mind.

But then I’m from the dark ages and haven’t tried tubeless. 😮

Tubeless has been a game changer for commuting for me. Pre-tubeless, most punctures were thorns which aren’t an issue now. Only one occasion in past year or so where it failed due to glass cutting a gash in the tread. Fixed with superglue and a tyre patch though.

Right, onto the wheels. I have other wheels on Hope Pro 4s, so having the same hubs would be a small nicety, over and above being a decent hub.

The Pro 4 hubs weigh about the same (188+311g) as the Shimano HB-MT400 (188+311) currently there, and it’s at the centre anyway. I read the Hunts will have a light hub to make the headline wheelset weight, but being near the centre it shouldn’t make much difference.

Rims: WTB i30 SL (OEM) 587g, Hunt XC 25mm 440g, Silt XC probably the same, Hope Fortus 23 450g. Saving 300g-ish on the pair.

Spokes etc.: OEM with 32 spokes 543g, Hunt and silt unknown, Hope Fortus 23 with 32 spokes 446g. I worked these out from the weights of the rims, hubs, and complete wheelsets. Saving 100g-ish, and probably another 50g by dropping 4 6g spokes going down to 28h, so 150g-ish on the pair.

Those wheels will be chonky.

First stop is replace them with some XC hoops and 2in tyres as you suggest.

300g (26%) lighter rims on the pair, 150g (28%) lighter spoke/stuff on the pair.

The width, quality, and maintainability are other reasons to swap them, but I wonder how much of a difference that much weight would do to acceleration.

Now using https://www.omnicalculator.com/physics/mass-moment-of-inertia , selecting circular hoop, 622mm / 2 = 311mm radius. The 440g Hunt rim has 0.021 kgm2 in the direction of rotation, and 0.043 perpendicular to it. The 587g OEM rim has 0.028 and 0.057 respectively. So the lighter rim has 25% less inertia, which is just proportional to the weight. I was half expecting that it’d have a bigger effect through a square in whatever the equation is, like how kinetic energy increases a lot for small increases in speed. The spokes will have some effect too but will be minor and I’m not clever enough to work it out.

That is proper weigh weanery stuff right there. Do you ever get time to go for a ride after doing all the calculations?

The width, quality, and maintainability are other reasons to swap them, but I wonder how much of a difference that much weight would do to acceleration.

You will feel it but it will make no difference to actual speed or overall times. I ride a number of loops a lot as ride from door and have lived in same place for 20 years. It is surprising how my best times and any times within seconds of best times (typically times around an hour) are on such a mixture of bikes (fixed gear, single speed, CX, hardtail MTB) so I have given up worrying about overall times as there is so little in it and just ride a bike I enjoy riding the most.

+1 on don’t peer too closely at the numbers, particularly on that rolling resistance site. Because they test at standard pressures, and on a fixed wheel, it misses real life context. I’ve a set of tyres panned for being 3w more resistance – yet I can run them at a slightly higher pressure, stay comfy, and benefit from the lower resistance. Plus they actually grip.

I do find light wheels make a difference when you’re accelerating and decelerating lots. But when up to speed, not much difference.

Tyres – mrs_oab runs Conti Speed Contact and I run Conti Top Contact or Contact. Compared to our previous tyres (Giant own brand, Kenda CX, Schwalbe Land Cruiser or Marathon Green) and our sons Small Block 8’s they absolutely fly along, and are noticeably more comfortable. We’ve not gone for ultimate puncture protection – but have had one (pinch) puncture in 3 years and a few thousand miles.

The Continental’s touring tyres are made up to 47mm and thier gravel 50mm – and we find sub 40mm comfy enough. The Contact Urban Comtact (ignore the name) goes up to nearly 60mm. The Uber duty ones are heavy, avoid.

I guess I’m suggesting going with lighter touring tyres, and our Continental’s impress me in real world use.

Been there done that.
Here’s my whippet with terrano wets and speed rocker mudguards. If you are not riding mud I found this set up perfect.
I ride lots of mud so have now swapped to my beloved bontrager muds .
The guards still offer good protection but have swapped to a mud rocker rear and crud X-Large front purely because they are wider.
The muds are lots better in the mud but don’t seem much more comfy than the cross tyres.
Tubeless is a must.

Not actually got them fitted and rolling yet but for similar reasons (bike path and forest road committing options) I’ve bought the standard pattern Schwalbe G1 allround in 2 1/4 inch. For mudguards I’ve gone for velo 65 from SKS. Not as good coverage as proper full guards but more than a mudhugger type and cheap enough. Hopefully the stay will reduce the wobble that the similar shape beavertails on the kids bikes get.

VELO 65 MOUNTAIN SET

If I do swap the wheels they’ll probably be Fortus 23. Not impressed by the component parts of Hunt (Novatec hubs it seems) and Silt (Chosen hubs and Kinlin rims I read) wheels, given the similar price of Hopes and being UK-made. Slightly narrower than the fashionable 25mm, they’ll work for the tyres I want but not sure if it’s optimal.

For that sort of use if you’d be happy with <50mm tyre width, the SKS AL56s you mention are ideal. It’s not just the width but also how rigid they are hooning along offroad: no rattles or hitting the tyres etc like I go with narrower tyres and chromoplastics.

50mm would probably be fine, but I haven’t found such a MTB tyre. Only gravel ones which are less durable.

I think the opposite may be true if you choose your gravel tyres wisely. A lot of the faster rolling MTB tyres in the 2.1-2.3 range aren’t that tough, and have only sidewall protection at most.

In contrast, the Gravelking SK+ (the ‘+’ is key here), Maxxis Rambler Silkshield and Pirelli Cinturato H can all be had in 29 x 2.0 (700 x 50mm) and all have a full bead-to-bead protection layer. They’re heavier than something like the Conti Race King Protection 29 x 2.2″

The G-One Speed 29 x 2.0 is also pretty tough (it’s actually about the same weight as the 29 x 2.35″ I think), but it aint a mud tyre…

I went for

Just Riding Along Monitor 25mm
Cross King 29″ x 2.2 ProTection, Race King 29″ x 2.2 ProTection
Velo Orange 700c x 63mm, Problem Solvers Fender Flute, Portland Design Works Safety Tabs

Glanced over quite a few gravel tyre and wheel reviews, and 23mm rim isn’t wide even in gravel terms so the Fortus 23 were out. The Pro4 is probably noisier than ideal around town too. Hunt and Silt I wasn’t keen on what I read about the Novatec/Chosen hubs, also didn’t like the noise of the Silt. Much better experiences on here with the Bitex hubs, and they have bigger bearings too – same size as Hope.

I bet you will really notice that combination feeling faster accelerating and rolling. 👍

Strewth, talk about over thinking this. Shove on which ever narrow near slick you can find in the shed/shop. Cheap is good as you may not like it. Almost anything can be made tubeless with an extra layer of tape. If you really mean gravel then something like a 35mm semi slick is perfect. Thats all I use year round in the FoD. I don’t ride mega mud climbs but everything up to the stupidly manicured red routes are fine as is most single track. 20mm rims were more than wide enough for 2″ tyres in the days of rigid MTBs and they still work as well today.
Mudgaurds. Only one thing is anygood. Something that goes a good 180 degrees on the back from BB to the other side. Then add a mudflap to keep you mates happy. SKS are fine. Mine don’t rattle. At the front take it past 1 o’clock minimum and add a soft flap that nearly drags the ground at the back. I have about 10mm clearance and they never clog up.

I’ve a unit X and use Mezcal 2.6 on the front and Bonty XR2 rear, which speed things up a bit and the weights are pretty decent for the size. Both available in smaller sizes.
I’ve also looked at smaller XC tyres for speed and light off-road like you suggest (not for winter mud-plugging) and thought of the following:
Maxxis Crossmark ii 2.25
£££ Teravail Rutland 29 x 2.2
Hutchinson Kraken 2.3
Pirelli Scorpion XC RC 2.2 or 2.4
Michelin Force or Jet XC2
Goodyear Peak 2.25
Specialized Fast Trak or Renegade?

Mudgaurds – I’ve got VO ones on my gravel bike and they’re brilliant. Not too heavy, quiet, superb coverage, nice fitting.

Cheers. It’ll be interesting to see if I’m still happy with the rigid fork after swapping the 2.6 for a 2.2.

Mudguards have arrived and the quality is apparent. Didn’t get mud flaps, might need the short one for the front though.