Johan Bornman

The SRAM range has XX at the top, then XO, then X9 - sortof like XTR, XT and SLX with Shimano. Most bikes are specc'd witha mix of the components. The most visible component is the rear derailler and this one is always from a top end gruppo. Then the crank. The rest gets skimped on. In your case, the brakes are an upgrade from the rest that's X9 - unusual.

The carbon/resin mix as used in bike frames is completely intert to water and most other things. However, a frame is very seldom pure carbon. Most have aluminium inserts in the BB. It is an alu sleeve glued into the frame. Should water get into the frame and come in contact with the aluminium sleeve, you get galvanic corrosion which destroys the BB insert. I've seen this on Cervelo frames. It is never a good idea to have water sloshing around your frame. Drill it.

The solution is to drill a drainage hole in the BB. Water will always enter through the seatpost/frame connection and cannot come out without a drainage hole. It damages the alu but more importantly, it rots the BB from the inside. Drill it.

I respecfully disagree with Hardtailoke. Avid brakes are the pits. The bleeding procedure is tedious, unpredictable and unsuccessful a large percentage of bleeds. Don't do it unless you have to. Why would you want to replace the fluid in the first place? But like he says, buy the kit and follow the instructions to the letter. But don't expect instant success though. It is a bitch.

The assumption seems to be that all bikes are created equal and that all thus have the same bearings. The other assumption seems to be that it is only bearings under threat. There is more to it. Two important truths about rotational seal design are: 1) A single seal cannot separate two liquids and paradoxically; 2) A seal that doesn't leak, leaks. Point one. If you have two liquids - water and grease/oil, you cannot protect the bearing with a single seal. Good hubs thus have a contact seal as the inner seal and a labyrinth (non-contact) seal as the outer seal. A labyrinth seal can be visualised by holding your hands in front of you whilst making two Cs with your fingers. The right one will be a mirror image of the left and reversed. Now lower your right hand until the two Cs intersect and bring it closer together. The cavity between them will be S-Shaped. Now rotate the two against each other and you have a visual representation of a labyrinth seal. It does't make contact and is only splash-proof, not submersible. The second seal is a contact seal or wiper seal. It has to follow law number two. Point two: If a rubber seal is not lubricated, it will burn away and no longer seal. Its lubrication comes from the inside and is the same grease that greases the bearings. It is designed to slowly leak out so that the seal is lubricated. The grease inside the bearing is thus a consumable and once there isnt enough left in there to leak out, the seal burns and stops making contact and stops working and hence stops burning. By burn I mean rub away like an pencil eraser rubber on a table. The fact that the seal leaks is evident from bearings. You'll see after use that the bearing pushes out a little bit of grease. Now, since the seal actually leaks (so that grease can come out) it also allows water to come in. Water in contact with such a seal whilst it rotates, can get in. All good hubs are protected by these two seals. Most people erroneously refer to the labyrinth seal as a dust cap, which it isn't. Some components, like the right hand side of some Shimano rear hubs, are only protected by a labyrinth seal and water is easily forced into these hubs. Many headsets only have a labyrinth seal at the top and nothing at the bottom. That's because water usually drips onto the bike from the top. (They seem to have forgotted about the stream of water shot up by the wheel, but that's another story). Some hubs, like DT Swiss and Mavic, are very poorly designed an either side and have no labyrinth seal protecting the bearing. Water is easily blown into these hubs. Hope hubs juse a combination of O -rings in addition to the cartridge bearing's own seal. However, between the freewheel body and hub itself, is a plastic ring that doesn't make contact and acts as a sort-of labyrinth seal. Not submersible and will certainly leak if sprayed. Modern external cup BBs are also poorly sealed. The plastic press-fit spacer is a disfunctional labyrinth seal. BBs in BB shells without drainage holes are particularly vulnerable from water entering from the seatpost and eating at the bearings from the inside out. Cable ends are not sealed against water at all. Even a light spray easily penetrates cable housing and ruins the cable a few weeks down the line when it starts to oxidise and become tardy in moving around. Most mountain bikes ship with exposed cable runs and it is easy to see what water does to this. We have discussed this here often and it is not difficult to see that an, even gentle spray of water, will do to these cables. Pedals, especially slightly worn Shimano and Crank Bros pedals have very delicale contact seals at the inner end of the axles. Once these are worn, water is easily blown in there and trapped against the small little bearing that quickly rots. Lots has been said about how tough seals are. Well, they're not. If you inspect them you'll see that the rubbing end is a thin, tapered lip that is easily flapped around by a bit of compressed air or water jet. However, this is not the big issue. Once they are slightly worn and no longer making contact, water will penetrate very easily. Although a bearing with a worn seal is not completely destroyed yet, water in there will just cut its life short. Sprayed water also carries contaminents with it. Shifters - mountain or road, have open designs. All that protects it is an unsealed cap. Grit and muddy water from road spray easily penetrates these and impairs function over the long run. I remain convinced that a long ride on the roof of a car is not good for the bike.

You make sense. If you could wrap something around the bearings, such as the headset, hubs and suspension members, it will slow down the water and prevent it from slipping in underneath the contact seals. Contact seals of the type on catridge bearings (which are plentyful in headsets, BBs, hubs and suspension pivots) are easily overpowered by pressure - be it air or water being aimed at it. They are really just designed to be splash proof. If you can protect them, they'll survive. It is no use attempting to lube everything afterwards, you're just mixing grease and water then, which will emulsify and will destroy the bearings. The trick would be to get the water out, which is impossible. Those seals will keep it inside, very effectively. By putting the bike behidn the car you're putting it out of the direct air/water stream where the water is misted onto the bike rather than sprayed directly at it. However, a wheel that peeps out is still vulnerable.

Cynicism doesn't equal common sense. You're living proof of that. Think about it. You're driving through the water at 100kph or, you are standing still and aiming a 100kph jet of water at your bike. It is the same thing. However, you seem to think that taking a shower is the same as getting sprayed by a fire hose. Tell you what, it is raining outside ride now. Get in your car, crank it up to 100kph and put your head out the window. Don't wear your Oakleys. Come report back to us cupcake.

Yes. It will do damage. Water will get into all the bearings. If you can, put it behind the car.

If I'm not mistaken, Eeccentric here on the Hub has a tandem or two, one of which is a Titan. He was explaining to us the other day how they all have a common hanger. Contact him. Hendriiiiiik! jou foon lui.

No

That is the OD and ID of the bearing. That is a whole minefield in itself. There are about 40 variations of these things and that's why it is best in the long run to stick to a standard. Companies like FSA make bearings for most of these proprietary sizes but that's not doing us any favours. The followers of stupid sizes and angles should be squeezed out of the market.

A 45/45 degree headset bearing is evil. It is some propietary standard perpretrated by the likes of Richie and its band of merry colluders. The standard was set by Cane Creek (then Aheadset) in the late 1980s and calls for 36 degree/45 degree. That standard was widely licenses and 36degree bearings are cheap and plentiful. Finding 45 degree ones may be easy, but I'll rather pay R50-00 for a quality 36 degree one than R275 for an equivalent one of 45 degrees. My approach to this is to replace the headset (often for less than the price of two 45 degree bearings) and make sure it conforms to standards.

No. The Max bearings have a tighter contact seal (rubber) than LLB bearings and, 30% more grease. Max bearings are designed for small oscillating movements whereas the LLBs are for rotational movements. Having said that, no deep groove ball bearing likes oscillating movements. Hence suspension pivots that fail so quickly. Metal seals are non-contact seals of the labyrinth type and totally unsuitable to any bicycle application.

PM me if you are interested or sommer send me an e-mail. I have a limited supply of them, as well as Koolstop salmon thin-line brake pads that go with them. This combo stops a train without squeal, blood, sweat or tears. Even in the wet. I said earlier they were M-750s but they are even older M-739. It is quite strange that the newer ones don't have the linkage but I think as disc brakes phased in, they weakened their V-brakes on purpose. How's that for a conspiracy? I also believe in the Illumininati, aliens and ghosts.

Those big rear wheels and some of the impliments attached to tractors made me think of sosaties and mincemeat each time I used to catch one. I sat behind a TLB once for a couple of k's. He had his hazard lights on and happily bounced along at 25 or so kph. Eventually I decided to pass and I went around on the right like any good road user will do. However, the driver decided to turn at the same moment. He pushed me over and forced me to turn with him. Several washers were pinched out of my saddle's leather. I didn't know he was going to turn since he had is hazard lights on and in that mode, the indicators don't work. I've since given a lot of thought to European laws that prohibit cars to move whilst their hazard lights are flashing.

You haven't lived until you've chased down a truck and sat in its hot, quiet slipstream. The onliy think nicer than the moment you know you've got it and can sit in the slip, is arriving at your muffin stop 20 minutes earlier than your chicken buddies in the pack. Unfortunately I'm too slow nowadays to still catch trucks but I sure miss them. Maybe I can find a fat, overloaded old brick truck somewhere and catch him for old-time sake. One think you must remember - any truck, no matter how overloaded it is, can stop quicker than a bike. But I'm telling you this not to put you off, but to clarify a point that should really be discussed in Tech Q&A - one day.

It should take you ten minutes to test it the way I described. Maybe 15 with removing and refitting. Your rebound problem sounds like too thick oil. Unfortunately this is not a DIY issue. As for the EP90 oil in a Rox oil bath? No. It is far too thick and will not splash up from the bottom of the fork to the insides of the seals. If you're in a pinch, rather use engine oil, one of the thinner ones like 5 or 10W40.

Clint, your last question is directed at the wrong person. I'll never let a bike shop do it for me. At the very least you should try it first and then hand it over to someone else. Remeber, if it aint broke, fix it. Tighten spokes so that the wheel runs true. Obviously you should pay attention to those that are obviously loose but thereafter you only worry about tension and trueness, not feel of individual spokes. You want as much tension in those wheels as you can get without the spokes twisting so much that you cannot get more in there. Buy yourself a nice spoke spanner. Get a Spokey (yellow) from CRC. But for now, but one of those crappy multi-side ones that cost a dime a dozen. They are good enough for the occasional wheel true but you don't want to do serious work with them because they slow you down and irritate your fingers. You want a single-size spanner you can keep for life. Something that very few bike mechanics know is that a perfectly true wheel cannot have even spoke tension and conversely, a wheel with even spoke tension cannot be perfectly true. This is due to imperfections in the rim. Give it a go, it isn't difficult if you just think about what you're doing.

Martin, I'm willing to bet that the frame in this picture is coated with something. It looks just too shiny for raw alu that's not fresh from the polisher.

Yes Uncoated aluminium oxidises very quickly. Within minutes it already has a layer of aluminium oxide on which ironically, protects it from futher oxidising by slowing further oxidising down. However, it turns a dull grey and wherever it touches your skin or white shorts (you do wear a white pant, don't you?) it leaves black marks. Not nice. Further, sweat and salt will almost certainly speed up the oxidising (even with its protective oxide layer) and leave large ugly white crystals. Just coat it. Even a spraycan of clear lacquer will do the trick.

There are V-brakes and then there are XT-M750 V-brakes. The latter are superb. You can do much much better than those Tektros on your bike. Look for a set of old XT V-brakes with parallelogram linkages. These keep the pad absolutely square with the rim and makes braking a pleasure. The difference is chalk and cheese. And if you really want to spoil your bike, fit Koolstop salmon thinline pads to those XTs. It improves the tandem experience dramatically. I've done several upgrades like that for my customers and they all smile. I recently came across new XT V's and they're no match for the real thing which were developed when Vs were all we had. Nowadays they're all watered down sans parallel linkages.

My guess is that the oil is not up to scratch. Unfortunately the only way you'll know is to change it and that is not trivial. I'd do one test before I send it back though:. 1)Remove the shock from the bike and deflate it (very important step this). 2) Clamp the propedal-side eye in a vice and unscrew the air cannister. Some clean, clear blue oil should drip out. If not....someone bulshitted you about the service. 3)Remove the air cannister completely. 4) Now with the shock still in the vice, pump it in and out and see if you can simulate the squeak. This should be easy to do since you're now only working against the damping mechanism and not the spring. 5) Manipulate it in all the settings. If the squeak is there, it is back to the original fixer. 6) If not, I'll check the lubrication on the air cannister seals and main piston seal. There should be fresh rubber grease on there and everything else should still be clean, if somewhat oily. 7)Replace the cannister but first grease its screw-in side's edge with rubber grease. This end engages with a thin O-ring and you dont want it to fold when turning. Oh yes, replace the oil that you lost with a teaspoon-full if EP-90 gear oil or similar.

You are talking through your nose. I'd like to see you break a spoke by tightening it at the nipple. @OP - truing a wheel like that isn't as difficult as it sounds. Follow these steps: 1) Find the loose spokes. This should be easy. You should be able to feel them, spot them with your pencil test or hear them if you pluck the spokes. Remember, that the spokes on both sides are not at the same tension (unless you have a road bike front wheel). Compare side with sides, not with opposite sides. 2) Now for rule number one. ONLY TIGHTEN SPOKES. Yes, that's right. A spoke cannot tighten itself but it can loosen itself. Therefore you only tighten. Keep on tightening in small increments until the wheel runs true. 3) That wheel went out of true because the spokes did not have enough tension to start off with. If you are brave enough, you can now tighten all the spokes equally so that the wheel ends up with higher tension. I suggest one turn to each spoke and then maybe another turn to each spoke. Don't turn twice at once. You'll know when you reach maximum tension, since the spokes will start to turn with the nipple. If you can't see it, put a black permanenet marker mark on each spoke so that you can monitor whether it turns or now. If it turns, you overshoot the spoke spanner a little bit and then return. In other words, if you want a full turn, give it one and a quarter turn and then turn it back a quarter. The spoke will now be in the position you started and have no residual twist. 4) If the nipples make noises, it means you're nearing the maximum tension you can get into that wheel without lubricating the nipples. Unfortunately to do this, you have to loosen all the nipples until you can see thread, oil the spoke thread and nipple/rim interface, and start all over again. Dont go this far if you are not skilled in the process. 5) Once you have increased the tension of all the spokes equally, (i.e. turned the nipple say one turn on them all), your wheel will no longer be in the centre of the frame. The side with the slacker spokes (left on the back and right on the front)will be closer to the frame than the other side. You now have to put more thension on the opposite side - try 1/4 turn on each of that side's spokes first and see if it more or less in the middle. ON a MTB it doesn't have to be precise for what you're doing. A wheelbuilder can do it for you at a later stage. All you want to do now is get the bike going. Need I say that you use an upside-down bicycle as a truing jig I want to stress that there is NO way you can break a spoke by giving it too much tension. provided you don't allow the spokes to twist, you'll strip the nipples long before the spoke goes into plastic deformation.

He packed his stuff, sold his jigs for scrap, sold the tools, sold the plot and moved to Cape Town. I have no idea what he's doing there but he has to be around doing something in this industry. I'd like to find out myself.

Yup, it was written by humans and if we believe the supposed time-frame, it was written by humans who thought the earth was flat, shooting stars were visiting gods, ghost were real, killing something on an altar would appease invisible beings and unexplained phenomena were there with compliments of happy or angry gods. I accept that it is a parable, but then we have to cast doubt on the script in its entirety. Who are we now to say some bits are embellished and some bits are for real. Jesus wasn't around when the alleged resting period happened, so your Jesus is a man and therefore needed to rest and set that example explanation doesn't hold water. Besides, when he eventually took the cue to come on stage he was a god walking on earth posing as a man. I don't see why he needed to rest. This is just so convoluted. So why didn't he just command them to rest? Why the baby talk that confused the pious for centuries and centuries? Why didn't the ten commandments just have a few simple lines that would have sorted out all the ambiguity - don't exploit your underlings - don't enslave people - etc etc? This sounds like a normal day to me. Either they were resting, or they were shopping. Which one shall it be? You confuse me. Either god rested on the seventh day (or first day or whatever we call Sunday today) or he didn't. Either the bible is god's word or it is a meme eventually recorded in script. It can't be both. Either we follow the rule as written in this script or we interpret it as a tale and apply or don't apply it.