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A mate's mum needs a new front derailleur. The current one is a Sora fd-3304 for a triple. What will work as a replacement? Will any Shimano road triple fd of a similar vintage do the job? Even better, does anyone have a dead cheap replacement they'd part with in decent nick that they'd be willing to post to Leeds?
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if the headset has brindled
If the headset is brindled, I'd suggest replacing it. Brownish with streaks of other colours isn't generally a sign of good bearings. If the headset is Brinelled (technically false-brinelled), you can sometimes get more useful life out of it by increasing the number of balls (not the size) by replacing caged balls with full complement loose balls. Replacement of the damaged races is still the preferred course of action.
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does anybody know what length bottom bracket I would need to line up a Miche Primato crankset with a 6 bolt cog on a flipped shimano mtb rear hub?
One so long that it doesn't exist*. The nominal chainline on Primato square taper is 42.5mm on a 107mm axle, the minimum chainline for a 6-bolt flat sprocket on a 135mm rear hub is 54mm
*This is hyperbole - a 131mm BB, which can be obtained quite easily, will get you close enough. You need to check with long BBs whether they're asymmetric, for example a 127mm or 128mm offset BB might also work.
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Thank for correcting my spelling error.
The taken as read is the change to loose bearings hence asking the grade, as caged bearings don't come with a grade listed on packets I have seen.
The increase to 4.5 mm balls on the bottom race /crown race is an old trick so the balls can't sit in the dents so headset gets to survive longer. With the same size balls, the balls can still go in to the dents made in the races.you just hope by adding more that dents no longer match up.
We could go and discuss if you should use chrome or stainless steel but each has advantages and draw backs. Are chromed steel bouncier, does stainless wear more? You decide.
All I say is use an automotive marine wheel bearing grease. Helps the grease say where it is supposed to be.
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The increase to 4.5 mm balls on the bottom race /crown race is an old trick so the balls can't sit in the dents so headset gets to survive longer
A 4.5mm ball in a 5/32" dent just sits on the rim with a high pressure curved line contact. It rolls through the dent better than as 5/32" ball at first, but the extreme contact pressure just means you very quickly have a 4.5mm dent. A 4.5mm ball is sufficiently oversize compared with 5/32" that it's bigger than the raceway curvature in typical bearing designs, which isn't a good place to be.
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Isn't grade ten the best? Have read that campag use grade 25 in their wheels and headset but no idea if true.
Grade 100 should be okThe grade 3 is the best, followed by 5, 6, then 10, 25, 50, and on. Grade 50 are general industrial grade, where things need to work for months or years without fail. Grade 100 will definitely be OK, as long as the headset is kept adequately compressed, lubed and clean of contamination. I’ve also read that Campag use G25 bearings, which is great but general users would get better performance from G100 bearings that they look after a bit, vs. G25 bearings that are neglected.
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Now this is the third time that I'm writing this. Now feels like the web hates me.
This is a lower races and are already on the way out. The bigger ball bearings give it longer life. This races are not that precision machined. Have you ever checked the curvature of the races? Checked the relation to the race to the top of the mount.
These things aren't precision made so wouldn't worry about something that isn't rotating just occasionally wiggling.
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Sorry wasn't clear, grade 25 is the very best I'd use on a bike, as we both have read that campag use that grade.
Have found that buying 250 balls a time that the 100 or 50 grades are the same price. Reminds me that I need a restock as I have indexed headsets to clean and rebearing.
EDIT Jinxed myself, took first headset apart, it is caged ball bearings and the grease is just a sticky mess of gunk that brake cleaner isn't shifting.
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Ok, how do I identify the headset of a Kona dew, with out removing it? It is not an integrated headset, suspect that it is an aheadset traditional external cup 1/8th headset. As aheadset is written on the bottom cup.
The headset is notchy, I've taken the forks off and the ball bearings are caged and full of very dried grease that mannol brake cleaner and wet wipes are not helpful remove. So I can't clean the the headset races or the caged ball bearings, and regrease so I can make the the bike at least useable what should I use? -
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I don't know what powermeter you are referring to, but crank based powermeters work by measuring strain in the crank arm. When you push on a pedal, you are notjust bending the crank arm in the main plane of the bike, but you are also twisting it. There is a chance that the powermeter manufacturer has created a stiffness profile of the crank in question and loaded that into the firmware of the device.
What is the calibration method they suggest? If they don't know the stiffness of the crank you are mounting it on, it will be quite a difficult thing to do at home. -
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It seems like Avio are out of business now? CAlibrating with a 10kg weight will not be accurate at all. A home gym weight could easily have 2% error, you are only calibrating in one orientation (horizontal crank), you are calibrating with around 10% of your expected values so any error in calibration will be magnified at higher forces... I wouldn't trust that device to give accurate power numbers.
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... I wouldn't trust that device to give accurate power numbers.
There are very few circumstances in which accurate power readings are important. I wouldn't trust it to be precise either, but if it were precise then that would be sufficient for almost all purposes.
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Now that seems like a real task, as I would have to strip down the forks. Tried white spirit and automotive tar remover to remove the gunk in the races. In the end, sodium hydroxide oven cleaner on a cloth for 30 odd minutes removed all the black gunk. The caged ball bearings are shiny but the cages are full of gunk.
@Netakure agreed with your diagnosis, the current headset is an aheadset brand headset and you can buy individual parts so the bottom cup and fork crown are purchasable for less than a tenner. So doubt the quality is high.
But cleaning the races up I can't see, with a loupe or feel with a fingernail any marks.
What is most annoying is that I bought 2 of these type of headsets (xlc brand) from Halfords and I can't find them.
As I need to fix this bike, as all my others need work too. I'm going to replace the caged ball bearings for loose. Then fill with either Lucas green grease or ront brand blue marine grease.
EDIT Went to mercury bearings in Enfield and even tho they stock the ball bearings they have no idea of grade, and looking at over £10 for 100
ltc
gbj_tester
lynx
Muc-ed-off
Kimmo
Netakure
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Mechanics and Fixing Any Questions Answered
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Should be something here https://www.sjscycles.co.uk/brake-spares-other/