Dahon Mariner D8, gears skip 7-6-7
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Dahon Mariner D8, gears skip 7-6-7
I recently bought a new Dahon Mariner D8. So far, I really like the bike. My one issue is when I'm riding is 7th gear, it periodically (every 100 yards or so) downshifts to 6th then immediately back up to 7th without me touching the shift levers. I tried readjusting the rear derailleur, but I'm not that sure if I did the B-tension correctly. Could this problem just be in my adjustments? or an issue with the cassette or the derailleur. I'm posting here because there doesn't seem to be a Dahon dealer anywhere near where I live (closest is over 150mi away), so it is not trivial to get the bike to an 'authorized' Dahon service tech. Thanks in advance for any help.
#2
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It's enough of a problem that I'm about to put a better derailleur on mine. I know how to adjust indexing but I can't get that Altus mech to work to save my life. I've heard there's a lot of slop in them and the rumors are true!
#3
Newbie
Or Acera M360? Took a little longer, but extremely smooth shifting.
I replaced the M360 with the Claris because of the Shortcage.
However, I kept the M360 as a spare.
#4
Stardust
I had a similar problem with a Shimano Acera RD-M360 on a Speed D8. It jumped between 4th 5th gear like you describe. The problem was a slightly bent RD hanger. I bought a hanger straightening tool online and straightened it myself. Worked smoothly after that. I've since upgraded to a Shimano SORA RD-R3000-SS and 11-32T cassette and this setup also shifts smoothy.
#5
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I'm not convinced. The OP said that it is shifting up and down. That sounds very much like a misbehaving Derailleur, not like a hanger. In addition, we are talking about a very much lowgrade Derailleur, Shimano's lowest grade.
#6
Hello
Don't forget to double check the limit screw to ensure it is allowing sufficient derailleur travel onto the seventh gear.
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Hi there, thanks for posting. For something like this, you should be able to visit any good local bike shop and get them to take a look at this for you. Due to the differences between the derailleurs on DAHON folding bikes and those on regular bikes, it may be useful to have the DAHON Service Instructions Manual to hand as it has a section about derailleurs. You can find this manual on dahon.com > support > manuals > service instructions.
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Thanks
Yan
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Bicycle delivery worker for Jimmy John's. Delivering is the best workout I have ever had.
#9
Hello
I would suggest the OP get the Shimano Document for his derailleur and adjust it according that procedure before he buys a new derailleur to solve the problem.
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I would not buy a new derailleur. Keep an eye on the hanger...it may be bent. That will mess up the shifting.
Thanks,
Yan
Thanks,
Yan
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Ph.D. Temple University ( Math )
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Sivananda ( Bahamas ) Trained Yoga instructor ( 2013 ) and ThetaHealer since 2013
Bicycle delivery worker for Jimmy John's. Delivering is the best workout I have ever had.
#11
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Yep, I just took a good look at mine and think it's a bent hanger. I'm going to put a big adjustable wrench to it and see how it goes. I'll post results later.
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I had a quick look on youtube and came across this video that shows it being tested with a drop test and shows the spring holding up quite well. Most Tourney's bounce all over the place allowing the chain to drop a lot of the time with such a test. I also think it should be up to the job on a single chainring bike like a folding bike. It could be a poor example of the derailleur but like others would suspect derailleur hanger or poor adjustment or maybe even some issue with the cable. It's the Mariner D7 that has the low end naff tourney drivetrain the D8 has decent components which really should perform very well properly setup.
Last edited by Bonzo Banana; 07-30-18 at 05:19 PM. Reason: update
#13
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My Mariner 7 came with Neos II.
Now it has Claris.
Inadvertently I did not see that Dahon changed from the later models Tourney now to Altus.
Now it has Claris.
Inadvertently I did not see that Dahon changed from the later models Tourney now to Altus.
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Thanks for the discussion. I was able to double check the limit calibrations using Altus RD-M310 specs from the Shimano webpage and they look good. Unfortunately, my test ride still occasionally exhibits the gear jumping from 7th to 6th and immediately back to 7th. Riding in any gear other than 1st thru 6th and 8th is smooth and shows no problems. Shifting is also smooth and problem free. Based on what I gleaned from the responses, it sounds like I really need to have a bike mechanic checkout the derailleur looking for a possible bent hanger. I'll ride the bike for a few more weeks avoiding long periods in 7th gear to see if any other issues manifest, then I'll take it to my local bike shop even though they do not deal with Dahons or other folding bikes. Thanks again.
#15
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I have exactly the same issue with my Dahon Mariner D8. It jumps gear 7 and goes right back in. It tired playing with cable tension and it didn't really do much. Then I just cleaned/lubed gears and chain it it's almost gone. It might jump raaaarely, but really does not. I guess it's a defect of the derailleur or gears that is present on many Mariners. I saw people complaining about it as well. Not critical, but an issue.
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I would guess that the rear derailleur is not in a parallel plane ( with respect to ) the cassette.
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Ph.D. Temple University ( Math )
Biked across the USA twice
Semi-active chess player ( two time Bahamas National Champion )
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Designer of Downtube Folding Bike
Ph.D. Temple University ( Math )
Biked across the USA twice
Semi-active chess player ( two time Bahamas National Champion )
Sivananda ( Bahamas ) Trained Yoga instructor ( 2013 ) and ThetaHealer since 2013
Bicycle delivery worker for Jimmy John's. Delivering is the best workout I have ever had.
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