Here at Pinkbike, we get inundated with all kinds of questions, ranging from the basic “Can I have stickers” to more in-depth, soul-searching types of queries like if you should pop the question or what to name your first child. Ask Pinkbike is an occasional column where we’ll be hand-picking and answering questions that have been keeping readers up at night, although we’ll likely steer clear of those last two and keep it more tech oriented.


Removing Tire Sealant For Racing

Question: @Travis-hutt24 asks in the Downhill Forum: Is it possible to seal a enduro tire with sealant and then use an injector to remove it for your race run (weight savings)?

bigquotes Well, simply put, yes. You can for sure seat and seal the tire, leaving it overnight to make sure any possible air exits are sealed. Then remove the excess sealant to have some weight gainz, with those being at the outermost reaches of the wheel, where their effect would be more profound. While this is all physically possible, it’s probably not advisable. I can understand the direction you’re coming from with the focus on racing, and that if you have a run ending tire failure then that’s it. But the sealant will also help fix any smaller punctures and issues along the race run that would otherwise then have more potential to end your race run prematurely if you choose to forgo the sealant.

For 60ml, or 2 fl oz, of a good quality sealant like Peaty’s Tubeless Sealant, you’re looking at 65g. Depending on your wheel size and preferred amount of sealant you could be looking at around a 130g weight saving per wheel, which isn’t insignificant.

All in all though, the benefits of the saved weight of no sealant don’t really outweigh the down sides of not having anything in your tire to fix mini punctures while on your race run.

Removing tire sealant for a race run would save some weight, but the risk of having a run ending puncture might increase.


Trunnion Shock Fitment

Question: @Levani56 asks in the Downhill Forum: Will a 225mm trunnion shock fit a Giant Glory? Right now I’m using 222mm shock, 3mm isn’t a problem but don’t know anything about trunnion upper eyelet.

bigquotes Short answer, no.

Long answer, nope. The trunnion mount is a different style of shock fitment compared to the standard eyelets. A standard eyelet uses a bolt that goes through the whole eyelet, pivoting on the bushing. A trunnion mount uses two separate bolts that thread directly into the shock, which still makes me wince every time I tighten those bolts

And while the eye to eye measurement might be close, the stroke of the two different shocks is also not compatible. The 225 trunnion mount shocks have a stroke of 75mm, while your 222mm long shock has a stroke of 70mm.

A trunnion mount shock, right, uses a completely different way to mount to the bike than the standard eyelet, left. The two are incompatible, although some people have made some sneaky conversion pieces to run non-trunnion shocks in trunnion specific bikes.


Spoke Lengths

Question: @haktor004 asks in the All Mountain, Enduro & Cross-Country Forum: I have recently wrecked my rear wheel and have to rebuild it with new spokes, rim and spoke nipples. The old rim has an ERD of 605 and the new 591, the old spoke length is 296mm. Is it right that the new spokes must be 7mm shorter?

bigquotes First off, the DT Swiss Spoke Calculator is a good go to for wheel building. You can use their library of DT Swiss parts, which will auto fill out all the dimensions, or input your own. The output will be the exact spoke length and recommended one to use, as sometimes the exact spoke length is a fraction of a millimeter.

For your specific case, moving from a 605mm ERD to a 591mm and as long as all other parts are the same (like your hub, nipples, spoke count and lacing pattern) then, yes, you’d need a 7mm shorter spoke. ERD being the Effective Rim Diameter.

A reputable wheel builder, be it in a shop or at home, would measure the actual ERD of the rim. Taking the ERD stated by the manufacturer is a good start, but the manufacturing tolerances can often lead to some differences in the real ERD. So maybe it’s best to take a look at some of the home setups for measuring ERD just to make sure you get the right spoke length for your exact setup.

Rebuilding wheels is a nice skill to have, and lots of people find the wheel building process less of a chore and more therapeutic. ERD, or Effective Rim Diameter, measurements are usually readily available, but measuring the actual rim yourself can make sure you get the right spoke length for your specific setup.


Replacing Fork Steerers

Question: @CN422 asks in the Mechanics’ Lounge Forum: I just bought a new take off RockShox Lyrik and the steering tube is too short. Can it be pressed out and a new longer one pressed in?

bigquotes Before we get onto pressing out the steerer, it would also be an option to buy a new steerer crown unit. Then you’d have a completely fresh and uncut steerer and the bonus is that your fork would get a rebuild with fresh oil to boot. You can find the SCUs online at many different outlets, or even sometimes in the Pinkbike BuySell for a bit cheaper, but it’s definitely possible to get hold of a new one through your local RockShox dealer. And if you’re curious, you can also use the SCU to play around with a different fork offset if that’s something that takes your fancy. Prices do vary where you look, but you’re looking at around $370.

So then, onto pressing. While I’m certain none of the fork manufacturers will tell you it’s the way to go, it is possible and there are companies out there offering this service. RSF Suspension in the UK, Honey Suspension in Barcelona, CJ Suspension and Shockcraft Suspension in New Zealand are at least some of the places I’ve seen this being done. ND Tuned are a Portugese company making aftermarket steerer tubes, and they could be a good point of call for finding a suspension shop close to you that could offer this service. Or perhaps people in the comments can help with American suspension shops that would offer this service.

Each method is going to have a price associated with it, and once you’ve got an idea of how much each one costs then you can make a decision on the best route to go for changing your steerer tube.


Insect Repellent

Question: @Beav asks in the Fitness, Training and Health Forum: Anyone use those bands to repel insects/insect bites? Seem to be getting bitten like crazy and i’m currently doing a bike 250 mile for charity challenge.

bigquotes Unfortunately I’m only seeing this a month after your post, so I really hope you didn’t get featured on too much by the little biting buggers, and that your charity ride went well. A tip of the cap for doing something like that.

Coming from the UK, I know your troubles trying to find an effective insect repellent. I’ve been up to the west coast of Scotland many times and been turning the air blue while fixing a puncture up in the damp, midge ridden hills. Similar experiences in Wales and New Zealand too with more midges, mosquitos and sand flies. At some point you’ve been bitten so much that you’re just a bit numb to the bastards.

But one product I’ve used a lot is Avon Skin So Soft, and given that you’re from the UK you’ll know all about Avon. Legend has it that the skin moisturiser was discovered by the British Army to be one of the most effective insect repellents available, and one that they use when on training missions up in those midge ridden Scotish hills. How much truth is in the legend, I don’t know. But it’s a good story and I can definitely attest to its powers of repelling.

I’ve also used Jungle Formula, which was also pretty effective. But then your skin wasn’t quite as soft afterwards compared to the Avon stuff.

Another option suggested by @Will1848 was to look into Permethrin, which you treat your clothes with and by all accounts stops bugs from even coming anywhere near you.

Anyone who’s visited Fort William, Scotland, will know about the midges – some of the ways to deter them get creative. Lots of products are available on the market ranging from creams to sprays and even treatments for your clothes.