Thumper Posted December 9, 2011 Share I regularly hit 100KMPH on my MTB!Does this mean I should stop riding when it rains? Link to comment Share on other sites More sharing options...
Slowbee Posted December 9, 2011 Share he he he he...same old same old... Been away for a month and NOTHING has changed.... you gotta loooove The Hub!!!oi, crazy frog, you doing the charity ride? Link to comment Share on other sites More sharing options...
Slowbee Posted December 9, 2011 Share So much of handbag slinging so early - looks like its PMS-Friday on thehub... you and the mrs going to join the charity ride ? expect to see the mtn bikes Link to comment Share on other sites More sharing options...
Captain Fastbastard Mayhem Posted December 9, 2011 Share Love the dedication in your experiment! Nothing beats personal experience! Link to comment Share on other sites More sharing options...
facepalm Posted December 9, 2011 Share Iam sure this will keep the water out. Dont knick it when putting it on. Remember to roll it all the way down Link to comment Share on other sites More sharing options...
davetapson Posted December 9, 2011 Share Lot of opinions again, but no fact. My pressure washer (and yes I use it to clean my bike) delivers water at a pressure of 110 Bar. The equation to get water discharge velocity: V = Sqrt (2 x g x h), where V is velocity, g is the gravitational constant and h is the water "head". To convert "head" to pressure: P = rho x g x h; thus h = P / (rho x g), leaving V = Sqrt( 2 x (P / rho)) This equates, without losses to 148 m/s. With a small round orifice like the head of a pressure jet, the loss factor is roughly 0.6. Thus the expected water velocity is 60% of 148 = 89 m/s 89 m/s = 320 km/h So no, at 1/3 of the velocity of a pressure hose, I do not think the water ingress will be a big deal. I believe that if it cant hurt you it cant hurt your bike. and very honestly, i did the experiment by sitting on a bakkie in the rain before, water at 100km/h does not hurt on your body (maybe a little on your face) You got to love engineers.Gold star for this man. Which reminds me of a chirp from my boet, who's an engineer, when some activist type chick asked him what the engineering dept were doing about the HIV/AIDS epidemic: 'We're engineers' he said, 'We don't have sex...'. Maybe you needed to be there. Edited December 9, 2011 by davetapson Link to comment Share on other sites More sharing options...
(Deon) Posted December 9, 2011 Share So here is rudi-h, seems he has knowledge on the topic. He shows some frustration at the responses but gets on with the explanation. Compare this to the style chosen by the other person and what it shows up is the fool hardy adamant response of someone who does not have a factual case, other than just to know. How is his opinion expressed? Through what seems to be anger with an unhealthy dose of sarcasm. TNT, if what you are in fact trying to say is, 'don't worry, your bike will be fine" say that next time and save us all your toy box tantrum. As a reader, once I read TNT's response I could not fathom out what made it a stupid question. The only advice we seem to walk out of a bike shop with is the one of, "DO NOT USE A PRESSURE WASHER". Since so little care instruction is given at the time of our new purchase, we tend to take anything that is voluntarily offered and hold it in high regard. i.e. They said so little, this must be important... This is the general trend of SA service, work it out yourself mentality. Is the hub going the same way? If I have, what I think is a good question that concerns me about my prized purchase, should I rather not ask it on a users forum? JB stated what most of us would think is the safer option... fortunately the tech has come far enough that we have good bearings hidden behind tight seals so if you only have roof racks, your bike should be ok. Link to comment Share on other sites More sharing options...
Wyatt Earp Posted December 9, 2011 Share ag bliksem mekaar net en kry klaar...olie ten minste net moving parts en bolts sodat jy nie roes kry nie :clap: But you have to love Da Hub, especially the self proclaimed super experts. Link to comment Share on other sites More sharing options...
Tumbleweed Posted December 9, 2011 Share Will do so. But then she is going to ask for matches. (Cheeky little bugger, she is...) Which she won't be able to use at 100km/h in the rain… Link to comment Share on other sites More sharing options...
428 others Posted December 9, 2011 Share I believe that if it cant hurt you it cant hurt your bike. and very honestly, i did the experiment by sitting on a bakkie in the rain before, water at 100km/h does not hurt on your body (maybe a little on your face) How many beers? Link to comment Share on other sites More sharing options...
Kranswurm Posted December 9, 2011 Share Plonkers........I had my old Cannodale with Headshok on the back and drove to CT thru torrential rain for hours.Within a few days the needle bearings and plates were stuffed.The oke at Cape Cycle Systems was adament that it was ingress of water from the trip.Why not.Its just a goddam cable tie which is not a perfect seal Link to comment Share on other sites More sharing options...
Iwan Kemp Posted December 9, 2011 Share So here is rudi-h, seems he has knowledge on the topic. He shows some frustration at the responses but gets on with the explanation. Compare this to the style chosen by the other person and what it shows up is the fool hardy adamant response of someone who does not have a factual case, other than just to know. How is his opinion expressed? Through what seems to be anger with an unhealthy dose of sarcasm. TNT, if what you are in fact trying to say is, 'don't worry, your bike will be fine" say that next time and save us all your toy box tantrum. As a reader, once I read TNT's response I could not fathom out what made it a stupid question. The only advice we seem to walk out of a bike shop with is the one of, "DO NOT USE A PRESSURE WASHER". Since so little care instruction is given at the time of our new purchase, we tend to take anything that is voluntarily offered and hold it in high regard. i.e. They said so little, this must be important... This is the general trend of SA service, work it out yourself mentality. Is the hub going the same way? If I have, what I think is a good question that concerns me about my prized purchase, should I rather not ask it on a users forum? JB stated what most of us would think is the safer option... fortunately the tech has come far enough that we have good bearings hidden behind tight seals so if you only have roof racks, your bike should be ok. Sense prevails. Link to comment Share on other sites More sharing options...
Grebel Posted December 9, 2011 Share I would rather transport on the roof than have all the k@k from the road thrown up by my own car all over my bike. Having said that though We drove to Sani Pass with our bikes behind our cars on a dirt road while it was raining. By the time we got to our destination, we could just make out the shape of a bike behind the car... A hose pipe sorted out the cosmetics and no ill effects for months to come after that. If I was you though I would leave the bike at home. Problem solved. Link to comment Share on other sites More sharing options...
Robrider Posted December 9, 2011 Share Lot of opinions again, but no fact. My pressure washer (and yes I use it to clean my bike) delivers water at a pressure of 110 Bar. The equation to get water discharge velocity: V = Sqrt (2 x g x h), where V is velocity, g is the gravitational constant and h is the water "head". To convert "head" to pressure: P = rho x g x h; thus h = P / (rho x g), leaving V = Sqrt( 2 x (P / rho)) This equates, without losses to 148 m/s. With a small round orifice like the head of a pressure jet, the loss factor is roughly 0.6. Thus the expected water velocity is 60% of 148 = 89 m/s 89 m/s = 320 km/h So no, at 1/3 of the velocity of a pressure hose, I do not think the water ingress will be a big deal. I believe that if it cant hurt you it cant hurt your bike. and very honestly, i did the experiment by sitting on a bakkie in the rain before, water at 100km/h does not hurt on your body (maybe a little on your face) There's one problem with your calculation. If I stand a meter away from the pressure hose, it definitely doesn't hit me at 320km/h. If I stand 2m away, it is barely a refreshing breeze. So there's also losses due to dispersion, and drag (or air friction), unless you put the nozzle right on top of the bearings, which will destroy them with out a doubt. You have also concluded that 320km/h will destroy the bearings, but a third of that won't... I don't see how that's a valid point, because what is the "cut-off" velocity that won't destroy your bearing then. Having said all that, I'm only commenting on the theoretical argument. I think its a stupid argument and I don't think it will affect your bike. If we really wanted to get technical we could look at velocity of water sprayed up from the wheels, effects of putting the bike forward facing on the roof vs side facing on the back, etc etc Link to comment Share on other sites More sharing options...
rob_mtb Posted December 9, 2011 Share I took TNT's approach once on a 5 hour torrential rain drive from Knysna back to CT. Needless to say, my bearings were stuffed when I got back. Had to redo the headset and all of my rear suspension bearings. I think the Glad wrap idea is great and I reckon that would have helped a bit. In hindsight, I think you'd be better off removing the forks and wheels, and maybe stick them in the boot, and Glad wrap the rest. Rain has a sneaky way of getting into things. I also think this TNT vs JB thing is really tiring. JB has a lot of good info on him, he's fixed and tuned my suspension before and he knows bikes. Who is TNT? Just some aggressive troll on the web hiding away who he is, constantly having wise things to say. Johan uses his real name, and stands by what he says with actual technical input. Who are you TNT? Please state your name and occupation. Link to comment Share on other sites More sharing options...
gummibear Posted December 9, 2011 Share I have always used municipal black bags and insulation tape to protect my bike when it's on my rack.Takes about 10-15 minutes to wrap and tape but your bike will be dry. Link to comment Share on other sites More sharing options...
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