Category Archives: Tyres

CRF300L: Lowering link

Writing up my 9000-km review over Christmas, I realised how much the Honda’s 35.2″/894mm seat height was bugging me. And it wasn’t just me. In 2023 Honda introduced a 2-inch-lower CRF300LS model, achieved by slightly shorter suspension components. An appealing non-red colour scheme apart, it’s otherwise identical, though currently not sold in the UK.

According to the guy above, no seat foam was harmed in producing the LS: ‘Honda shortened the suspension…’. But he then goes on to say ’rear travel is reduced by 1.2”’. Does he actually mean shock length is reduced by 1.2”’ (to make 2” less vertical travel)? Probably.
Riding the trails, my suspension travel is way more than I ever need – an LS would have done me nicely – though once compressed the height’s rarely an issue unless I tackle technical terrain. Very occasionally the back bottoms out as it should; the front not yet. With me it’s more the getting on and off, which I do a lot of and gets more tiresome as the years pile on. Along with comfort, these two things hold back my enjoyment on the L. Fitting the 17/19 wheel combo didn’t lower the bike significantly.

So I bought one of those suspension lowering links which I’ve read about for years. I recall my KLX had a clever adjustable link. US-made Kouba Link is the well known brand, but costs nearly £200 in the UK. I settled on a similar looking ‘Schmooba Link‘ off ebay for just £42 with the same needle bearings and grease nipple. NICECNC may be made in China but have a decent-looking website and a huge range of parts.
They say these links can mess up the carefully mapped factory linkage ratios working on the shock spring. That may be an urban myth or something that only applies to performance-sensitive racers. The link swap took just 10 minutes with a helping hand of Larbi in Marrakech.

My Schmooba claims to lower the bike by 1.75″ (44mm; identical to Kouba) which is a bit more than I need, but tbh it didn’t look that much lower. Once fitted, I jacked the Tractive shock preload up a turn and a bit. What a faff that is. The shock is clearly made for an HPA and not manual adjustments. The job is made harder with the need to loosen a grub screw locking the preload collar in place. The supplied multi-bit tool has a 2-3mm bit to get in there (left); you then need a 5mm spanner to turn it, as long as the screw is in an accessible location.

There is no crenelated preload ring to hook with a c-spanner, but a series of holes in the collar, like on a wagon wheel hub (above). The multi-bit tool is too short and bulky; a 5mm rod or screwdriver works better, you inch the ring round; it’s easier on the RHS, and I found it best with a 5mm L-shaped Allen key and an additional extension/lever. Give it all a squirt of WD40 too. It takes about 12-15 micro-adjustments to get a full turn of the collar. I kept going until the annoying grub was accessible again and hope that’s enough.

Of course the forks need sliding up the triple clamps to match the rear drop – easily done. But without risers, the stock height bars limit the drop to about 25mm. So 25mm it will have to be; I hoped the jacked-up shock would compensate for the now moderately raked out fork.

If you’re lowering your 300 you’ll need a shorter side stand. RRP do 20mm shortie for £88. Or so I thought. With forks raised and link fitted it actually didn’t lean too bad. It turned out a new oversized Mitas E07 tyre on the back raised the bike back up an ~inch. Then, offering up the RR short stand, it turned out to identical. Have I been on a short side stand all this time or did they send the wrong one? Oh well, one less job to do.

Fatter Mitas 130/80 17 TL E07; actually a good idea.

Is an OEM stand for the 300LS on Partzilla US shorter?
Two are two stands listed but which was which? Knowing that the 300LS model code is probably CRF300LDA ABS is helpful.

Lowered 300LS CRF300LDA ABS side stand: 50530-K1T-J70
My bike 300L ABS side stand: 50530-K1T-E50

In fact a -J70 shortie is bent; the normal height -E50 is straight. And if you look up 300LS reviews online you’ll see they have a bent side stand, unlike a normal 300L, even though the Honda parts fiche shows a straight stand for both parts. Hence my fiche confusion.

A J70 is discounted to $35 on Partzilla US. In the benighted UK an E50 is £48 but I actually got offered a bent J70, which was actually what I was looking for. Fascinating a?! But wait, there’s more! A bent J70 is shorter. The reason it was bent because a straight stand on the lowered LS might drag on full suspension compression. So it seems Honda bent and shortened a stock 50530-K1T-E50 to make 50530-K1T-J70 for the 300LS, but online fiche images appear identical.

Now, about an inch lower, I can afford to take some of it back with some neoprene seat padding, as before. But first I tried a pair of Moto Skivvies (review) – padded undershorts made for motos not cycling. I’ve known the name for years but the 300L has pushed me over the edge and into their shopping cart.

Riding the lowered bike
By the time I’d jacked up the rear preload a bit and had a 130/80 17 Mitas E07 fitted, the bike didn’t feel a whole lot lower. Measured, it’s now 33.5″/851mm with the forks raised up in the clamps all the way, so almost exactly the 1.75″ claimed. For the next 4000km over a month, the bike rode the same on the dirt; maybe a bit better all round with a fatter Mitas all round (now properly sealed for TL by the mechanic).

Getting on and off still wasn’t a whole lot easier. I use the footrest where possible, but having the tail pack on the side would ease a leg swing. Thing is, a tailpack is so darned easy; on/off in 4-5 seconds with a pair of Rok Straps. No other actions required and no side-panel scuffing.

The suspension still works great, just like it always did. I think the taller tyre may have touched the mudguard on one or two bottoming outs. I have to take a little more care when stopping and putting the stand down, but all in all, an easy, inexpensive and recommended mod if your stock L is giving you nosebleeds.

Tested: £20 USB rechargeable tyre pump

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My mate Robbo put me on to me this unbranded 4000 mAh USB rechargeable tyre pump. You’ll find the usual clones of clones of clones on ebay from around £20. Tbh, I don’t know what 4000 mAh means – battery capacity probably, not power, but it worked well for me.

Mine came with a bunch of unneeded nozzles and a Samsung-type USB recharge cable. You turn it on, set the pressure you want (which stays in the memory) and press the middle button. Off it goes, pumping up a G310GS rear tyre from zero to 27psi in about 5 minutes without getting hot and while being dead easy to read. There’s a torch, too.
Remember, with pumps ignore some notional ‘150psi!’ figure which they might manage in a small-volume pushbike tyre. It is the much less often quoted flow rate or cfm that counts. This one is probably a lot less than < 1cfm and all pumps will slow down as they pass 1 bar or so. It’s how fast they can keep pushing to a typical 25-30 psi (2 bar) that counts.

I also used it daily to top-up the slow-leaking rear tubeless tyre on my CRF. Yes, a bike-battery 12-volt powered compressor like my 20-year-old Best Rest Cycle Pump (left) can be about the same size, weight and power, but for quick, cable-free top-ups it’s one less thing to wire-up or plug in. It vibrates less and makes less noise than my old Cycle Pump too, and recharges off mains in a couple of hours. I’d guess it would take at least 30 minutes of pumping use to flatten the battery. I never got close and of course you could do it on the move via a bike’s USB plug or off a power bank.

The elephant in the pump room is of course the durability of unbranded Chinese gadgets, but that applies to 12-volt pumps too, if not everything. On a long trip I’d pack a manual pushbike pump (search ‘Crank Bros’ and go from there). But for what I do in Morocco I’ll retire the Best Rest and rely on this handy USB pump in the tank bag until it dies on me.

CRF300L: Tubeless wheels 3

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CRF300L Index page
Previously on 300L Tubeless Wheels
Tubeless Wheel Conversion Index page

Note: I rushed this job below and had a manageable slow leak from the 17, a meltdown on the 19 front arriving in hot Marrakech (fitted a tube), but the 21 I left at home has held its air fine for months. In Marrakech the mechanic re-sealed the rear in between my trips, cleaning then applying a continuous band of Puraflex. He’s doing the same to my 19 front. Summary: technique works if you take your time – days of curing – and do it right.

Note: I rushed this job

Rims are smaller but the 300L is no lower and rests the same on the side stand

It took so long to get my three new tubeless wheels made I’d forgotten quite why I did it. Oh, yes, the clear desirability of tubelessness, plus some experimentation with wheel sizes, notably a 19-er front which is 38mm less tall, 7mm wider and the same weight as the stock tubed wheel. Wheel builders seem to have long lead times, rims are not in stock, custom spokes need to be made and holiday needs to be taken. Once everything was in place and my slot came up, the actual job took a couple of days.

The Fly & Ride transporter was leaving for Malaga next week so I had to get cracking. Ideally I’ve have had a month or more to sort any sealing issues and get a feel for the new sizes.
The 19-inch wheel arrived so I got stuck in but rushed it. I didn’t wait a day for the glue to cure, then fatally used slippery 303 UV Protectant to help mount the very stiff AX41. Works great on tubed wheels but I suspected it was a bad idea for MYO tubeless. Once mounted, when I spotted 303 bubbling out of a spoke thread I knew the game was up.

With the tyre off, my glue blobs had gone soft (left, from 303 contact?) and peeled off like soggy plasters. To be fair, one problem with this used 19-inch rim was that the pre-existent spoke holes (from a KTM?) had to be reamed and re-angled to fit the Honda hub. It made for bigger gaps so I tried to seal the outside of the nipples with Stormsure where water might run in, but should have done a better job all round.
This is the gamble of marrying pre-drilled rims with non-matching hubs. Angle-wise, there can’t be that much in it, but in this case it was enough to misalign the pull of the spokes. Some wheel builders like CWC keep drilling patterns or templates to precisely drill a rim to match a given hub. This used Excel rim saved me £150 which I easily paid back with re-drilling and custom spokes. Oh well, the perils of experimentation.

Next day I needed to get my ducks in a row. Typically for me, I wasn’t repeating the proven system from the Africa Twin, but trying a new idea suggested by a mate. I spent a couple of hours in Poole sourcing components and by the time I got back, the other two wheels had arrived. After cleaning the 303 off yesterday’s mess, I started over.

**Wire brush** each spoke nipple. Didn’t really do much as rims were in good shape but worth a go. Mini drill brushes on ebay.

Rough up the rim’s black painted well with **sandpaper** then wipe it down with gas-o-lene.

**Mask** off the bead and lip with tape (did this a bit late).

Drip **runny Superglue** around the edges and into the thread hole of each nipple. Should pre-penetrate the cavities.

Spray the rims’ well with etching primer. Halfords were out so I paid £21 down the road. All for 60 secs of spraying ;-/ I presume the idea is the sealant sticks better to the primer than the glossy black rim.

Once dry, apply a blob of **Puraflex 40** to each nipple. That’s 104 blobs for 3 wheels but still < half an £8 tube, fyi.
**Individual blobs** as opposed to a continuous band like here are better for isolating leaks, as will soon be shown. But a **continuous band** ought to mean a guaranteed and complete seal. Decisions, decisions.

Let the Puraflex cure overnight, light a few candles and hope for the best.

Next day I felt fairly confident I’d sealed all three wheels but had some heavy tyre wrangling to do. Sod it I thought, why not support the local economy and let my LBS mount the tyres. They’ll have a tyre machine and a compressor with enough poke to shove the tubeless tyres onto the bead before they know what’s happening.
With 30 quid well spent, the tyres came out the shop rock hard. But would they stay that way? No, the two fronts were losing air. Casting aside seal damage during mounting, what were the chances of 104 blobs and 3 valves all being perfectly sealed? Only about 98% it seems. I turned the leaking wheels slowly through a trough of water and isolated a leaking spoke on each. I marked the spokes and whipped off the tyres, much easier now they’d been pre-flexed at the shop.

On the 19er I spotted a millimeter wide hole in the Puraflex (left) which the dab of Superglue underneath had also not sealed. I’ve not used Puraflex before – it’s not like a bathroom sealant and is PU, not silicon, based. Not sure what that means – the stuff was good and hard but had shrunk a bit as it dried. Perhaps the hole had opened up on curing, or perhaps I should have inspected each blob with a magnifying glass or given them all a pre-emptive second swipe of Puraflex once dried – that would take another day to dry. On the 21 incher I couldn’t see the hole under the corresponding spoke’s blob which underlines the idea of a second coat or even a continuous band. So I second-coated all the blobs and left it for another night. Weeks later the 21 (left at home) had lost just a couple of pounds so I’ll take that as a win.

All bolted on and first thing I noticed was the bike leant the same on the side stand, so clearly was no lower. Not that bothered as it’s one less thing to meddle with and the narrow saddle means my feet touch down OK. I guess the AX41s have high sidewalls; good for off-road and rim protection.
I went for a lovely evening ride. On the road the fresh tyres didn’t exhibit any anomalies, nor did the handling feel much different. I think it might take a more spirited ride through some bends to highlight any improvements in the steering. In Morocco I know just the spot, several in fact. The 19 is only 7mm wider than the 21, while the back 17-incher is the same as the stock IRC.

In Halfords I’d bought some Slime for later, but also carefully applied a shot of similar Tru-Tension tyre sealant (left) in the front wheel, squeezing it up into the valve set at 12 o’clock so it would dribble down along the rim’s well. This stuff contains ‘carbon fibre and graphene’ which are such cutting edge compounds I fell for it. Slime or similar have helped permanently seal other imperfect MYO TL jobbies, even though it shouldn’t be necessary if the job has been done well.
I rode back to London and then on to Fly & Ride near Gatwick. Whatever fuel I picked up in Poole, the CRF (now with 2200 miles on the clock) belted along like it was on methanol, holding an indicated 70 much of the time. But both tyres were still losing a bit of overnight air so I may have to spend a day in Morocco sorting it all out. I’ve packed Puraflex, some more Slime and a pair of tubes and levers.

Robbo, a fellow MYO TL experimenter does wonder whether Slime etc can soften rim sealants. These goops work under pressure but also centrifugally, getting flung out onto the inside of the tyre where punctures occur, but away from the hand-sealed rim well where, in my case, it’s as needed.
Much as Sixties psychedelic guru Tim Leary proposed that enlightenment and self-awareness must eventually be sought without the aid of drugs, so MYO TL should endeavour to seal without Slime. Tune in. Glue Up. Ride out.

Robbo showed me a niffy USB rechargeable 4000MAH tyre pump (above right) which topped my overnight tyres up quickly. I have my aged 12-volt Cycle Pump packed on the bike, but if I’ll be topping up regularly until they’re fixed, the 20-quid hand pump off ebay will be easy to whip out and use each morning. Let’s make rumpy pumpies while the lithium lasts.
I left my 300 in Fly & Ride’s yard alongside a cool ’72 750SS Commando. The period image on the left exists solely to highlight Norton’s questionable use of an apostrophe. It turned out the nicely set up 300 Rally also parked up belonged to another Robbo who was on my tour a year ago and by now is halfway to Dakar, or however far suits him.

So, a bit annoying to be flying out to Malaga next week to imperfect wheels, but what trip ever kicks off without some T’s uncrossed and I’s undotted? At least I have the means to fix it.

CRF300L: Tubeless Tyres 2

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CRF300L Index page
300L Tubeless Wheels 1
Tubeless Wheel Conversion index page

2 second version: I bought some tyres.

I’ll have spent a staggering £550 each on three handbuilt ‘MT’ wheels for my 300L, all so I can seal the rims and fit tubeless tyres for easy repairs and greater longevity. Oh well, it’s good to support the economy.
When it comes to tyres, people love to fit fatter but I aim to get the closest-to-stock size tubeless tyres that’ll fit the new rims. But as mentioned previously, the smallest available tubeless-ready, ‘MT’ rims are a size or two wider than stock 300L wheels which may mean wider / heavier tyres too. FYI my MT-type tubeless ready wheels will be:
Excel 17 x 2.50
SM Pro 21 x 2.15 (£50 cheaper than Excel equivalent)
Excel 19 x 2.50

Unsprung durch Technik
With wheels (not least pushbikes), unsprung weight (parts not supported by suspension, mostly wheels) exponentially affects acceleration/braking as well as suspension response and probably mpg and appetite. You know how I feel about mpg. Imo, efforts to limit rotating mass are worthwhile on a 150-kilo bike with only 28 horsepower. As I wrote while preparing the Him “… it’s why your Hoka trainers weigh only 320g [i.e: as little mass/inertia as possible to do the job]”. Adv riders go on about swapping pipes and ‘bars and batteries to save weight (while having to add it elsewhere), but tyre weight is rarely considered and can vary quite a lot.
My wider rims may weigh more, so might the slightly over-sized tubeless tyres. Overall, my tubeless conversion may barely save weight.

‘What tyres do you recommend?’
In line with EU diversity initiatives, I try and never use the same tyre twice. It’s good for the book, too. But when a mate donated a new Michelin Anakee Wild 120/70 R19, I thought I may as well go all-Wild, as I did with no regrets on the heavy Himalayan a few years back (left).

I was risking EU sanctions until I was reminded of my own words: a rear Anakee Wild to match the 19 comes no smaller than 130/80-17 but weighs a staggering 7.5kg – enough to give my poor Honda a hernia.

I don’t know if being a radial adds weight – apparently not according to this albeit contradictory article I found on the internet. And then I clocked my fat-tyre mate’s front 19er at a hefty 5.2kg – more suited to a CB500 than my simpering trail puppy. Barman, double hernias all round!

Back to the drawing board. Along with Kenda K784 Big Blocks, Bridgestone’s AX41 Adventure Cross (left) is a do-it-all 50/50 jobby I’ve been wanting to try. The advent of the AX41 a few years ago culled Bridgestone’s range of Trail Wings, some of which I’d have happily chosen for the 300L. What’s left in TWs are tube type and pitched as ‘retro’ (pre-Adv era) tyres.
Best of all, unlike Mich, Bridgestone do an AX in 120/80 17 TL (118mm wide – 1mm more than the stock IRC) as well as a nicely slim, 92mm-wide 90/100 19, plus a regular 90/90 21 at 85mm wide. These widths are all verified; you’ll find broadly similar AX41 width data listed here, but tyre weights are something you rarely find listed publicly, even in pdf online catalogues. I had to email Bridgestone Technik in the Netherlands who, to my surprise, promptly responded down to 3 decimal points:

BATTLAX ADVENTURE CROSS AX41 – claimed actual
Front 90/90-21 M/C 54Q TL – 4.428kg 4.6kg / 85mm wide. Inflated ø 696mm
Front 90/100-19 55P TL – 4.375kg 4.4kg / 92mm mm wide. Inflated ø 658mm
Rear 120/90-17 M/C 64P TL – 5.516kg / 6kg / 118mm wide

Nice numbers but as usual, manufacturers’ weighing devices seem to be calibrated sunny side up. Using the same scales, the rear 120 AX41 comes in at 6kg, still 1.5 kilos or 20% lighter than a 130 Mich Wild. My current rear IRC also weighs 6kg with tube – and such OEM set ups are often the lightest possible to eek out good performance figures from reviewers to whom longevity is not an issue. More numbers you say? The little used Mitas 4.00 18 trials tyre my 300 came shod with weighed 6.9kg with tube. And out of interest, I’m told the old favourite Conti TKC which I last used on a 660Z Tenere 15 years ago, weighs 4.1kg for a 90/90-21 TL and 5.4kg for a 120/90-17, but I recall they are quite soft or flexible tyres whiuch is why people love them on the dirt. As mentioned earlier, these tyres and tube combos work out heavier than the back wheel, at 5.4kg with a 40T sprocket and rim lock.

Meanwhile, the fatter 21-inch AX41 front weighs a true 4.6kg, 170g heavier than claimed and 200g more than current IRC with tube at around 4.4kg. The 19er is just what I was hoping for, it’s slim at 92mm and feels light, also at pretty much what Bridgestone say: 4.4kg. Height wise, unmounted the 21’s diameter is 27.4″ (696mm) vs 25.9″ (658mm) on the 19, at 38mm a bit less than the 2 inch/51mm variation you’d expect. And it only cost £83! Interestingly, all three tyres are Made in Japan. Not even Honda can manage that with a whole 300L!

Honda 21 wheel	SM Pro 21 TL	EXCEL 19 TL	Honda 18 rear	EXCEL 17 TL
3.9 kg	4.6 kg	4.4 kg	5.4 kg	5.6 kg

IRC 80/100 21 + tube	AX41 TL 90/90 21	AX41 TL 90/100 19	IRC 120/80 18 + tube	AX41 TL 120/90 R17
4.4 kg	4.6 kg	4.4 kg	6 kg	5.5 kg

Wheels (with rotors etc) and tyre weights. Spokes on new TL wheels are thicker

It’s eye opening that a set of wheels on a dinky, 150-kilo bike can weigh over 20kg, but they’re right at the coal face, dealing with all sorts of forces and impacts.
I think that on anything from 500cc and 45hp upwards, all this gram counting is unnecessary, but unsprung weight on a 300L matters. Will the seat of my pants notice the difference between a 7.5 kilo Wild and the 6-kilo AX41? Probably not without bluetooth telemetry, but I’d sooner take the lighter AX which still feels pretty rugged for a ‘250’ trailie.