Results 1 to 27 of 27
  1. #1
    mtbr member
    Reputation:
    Join Date
    Mar 2018
    Posts
    14

    Just purchased a bike...HELP!

    Hi guys, I started riding about a month ago purchasing a Diamondback Sorrento DB78 I believe it's the 2011 model (my first bike) which I now understand that I overpaid for. The bike shifts very rough into 3rd 4th and 5th gear in the back to a point where it interferes with the momentum of pedaling. It literally jolts the pedals while I'm pedaling as I switch which feel like a safety hazard. The front has 3 gears and the back has 7. While it's in the first gear up front it's not TOO bad switching the back gears. Once I'm in gear 2 or 3 in the front is when the issue begins. I tried to adjust the back derailleur myself but couldn't figure it out (i know I will figure it out I just need more practice and more patience) so I took it to a local mom and pop shop and got a full tune up. Took the bike out of the shop and realized that the gears switching hasn't improved much. Took it back, told him what was happening, he turned that little knob barrel while pedaling and said it was fine while I was standing right there and noticed through certain gears I heard a bit of rattling. I took it out and showed him how rough it switches, he agreed and said the reason for this is that it's my chain and my cassette that are both worn out and need to be replaced and gave me a $60 estimate and told me he wouldn't charge me for labor...why do I feel like I'm being screwed? Could It be my chain and my cassette that's causing these horrible shifts or is he trying to make more money off of my lack of knowledge? I don't know much about this and am still learning. If it's not those two what could it be? All I want to do is learn to ride, improve and not kill myself while doing it. Any information and help would be much appreciated. Thank you so much for taking the time to read a cry for help from a newb haha
    Attached Thumbnails Attached Thumbnails Just purchased a bike...HELP!-diamondback.jpg  


  2. #2
    mtbr member
    Reputation: MSU Alum's Avatar
    Join Date
    Aug 2009
    Posts
    3,242
    It's possible the derailleur hanger (or whatever the attachment is) is bent. That's very easy to fix. If that doesn't work, it may need a new rear cassette/chain, but the fact that it's the middle gears makes me think it could just be misaligned.

    As a general rule, never attribute to malevolence that which can be attributed to stupidity......in other words, I doubt they are trying to screw you, but who really knows.

  3. #3
    mtbr member
    Reputation:
    Join Date
    Mar 2018
    Posts
    14
    The hanger doesn't seem be to bent but what do I know? I'm attaching two pictures I just took.
    Attached Thumbnails Attached Thumbnails Just purchased a bike...HELP!-2.jpg  

    Just purchased a bike...HELP!-1.jpg  


  4. #4
    mtbr member
    Reputation:
    Join Date
    Dec 2017
    Posts
    462
    For the chain, measure the chain stretch. Lots of instructions on the web on how to do that. For the cassette, see if you can get some detailed close up shots (remove the rear wheel from the bike) and post them here. If you can, take a video of the shifting issue, post it on Youtube and post a link here. As MSU Alum mentioned, a slightly bent derailleur hanger will cause shifting issues too. Did the bike shop check that? If not, look on youtube for ways you can do that yourself. There's a specific tool that makes checking and aligning the hanger much easier, but you could make your own as well.

    EDIT: posted this at the same time you were posting your pictures. Hard to tell from those.

  5. #5
    BOOM goes the dynamite!
    Reputation: noapathy's Avatar
    Join Date
    Jun 2008
    Posts
    3,821
    Chain looks short and/or cross-chained.

  6. #6
    mtbr member
    Reputation: Flamingtaco's Avatar
    Join Date
    Mar 2012
    Posts
    1,453
    You could have the shop show you chain wear with a chain check tool, then you would know if your driveline is worn.

    That said, this being a 2011 bike, if it was ridden regularly, like even just once a week for 5 miles, and not even during winter, you're looking at about a thousand miles on the bike, and considering the condition it was in when you bought it, the PO most likely did zero maintenance, and that will definitely wreck a driveline in a thousand miles.

    I'd go one further than the shop. The rear derailleur is a cheap one that shifted poorly to begin with, and now being a bit worn, it's not worth a small bag of beans. The RD and cable is the first upgrade I would do on any low end bike as it makes a world of a difference in the quality of ride when shifts are quick and on target.

    MSU Alum is right on in suggesting you check the RD hanger for alignment. When you own a cheaper bike (or you didn't have to pay for it, like my kids), you tend to not care to be careful with it. I can guarantee that bike has been dropped on the driveline side a few hundred times, and that guarantees a bent hanger. My boys would think they were ok dropping their bikes in the grass because it doesn't scratch anything, but, yeah, with bent hangers and derailleurs and chain rings, the bike might as well be all scratched up because it rides like shit.
    I will suffer no butt-hurt fools!

  7. #7
    mtbr member
    Reputation: Flamingtaco's Avatar
    Join Date
    Mar 2012
    Posts
    1,453
    Quote Originally Posted by DimitriyGee View Post
    The hanger doesn't seem be to bent but what do I know? I'm attaching two pictures I just took.
    It can be bent enough to cause shifting issues, but not enough to perform a visual check. Got to put the tool on it.
    I will suffer no butt-hurt fools!

  8. #8
    mtbr member
    Reputation:
    Join Date
    Mar 2018
    Posts
    14
    I took some more pictures maybe this will help you guys see what I don't?
    Attached Thumbnails Attached Thumbnails Just purchased a bike...HELP!-3.jpg  

    Just purchased a bike...HELP!-4.jpg  

    Just purchased a bike...HELP!-5.jpg  


  9. #9
    mtbr member
    Reputation: DethWshBkr's Avatar
    Join Date
    Nov 2010
    Posts
    2,112
    Quote Originally Posted by DimitriyGee View Post
    The hanger doesn't seem be to bent but what do I know? I'm attaching two pictures I just took.
    https://forums.mtbr.com/attachments/...ike-help-2.jpg


    First off, that chain is WAY WAY WAY WAYYYYYYY too short. That derailleur is not even on the lowest gear, and is ABSOLUTLEY WAY BEYOND it's MAX. It should not be anywhere NEAR that tight. Is is INCREDIBLY LIKELY that the derailleur or the hangar have been bent as a result.
    "Go soothingly in the grease mud, as there lurks the skid demon"

  10. #10
    mtbr member
    Reputation:
    Join Date
    Mar 2018
    Posts
    14
    How does a chain become too short??? Is this something that happened during wear or was the chain changed the wrong way??

  11. #11
    mtbr member
    Reputation:
    Join Date
    Dec 2017
    Posts
    462
    Quote Originally Posted by DimitriyGee View Post
    How does a chain become too short??? Is this something that happened during wear or was the chain changed the wrong way??
    A chain gets longer with wear. Either it was cut too short when it was first installed, or something happened on the trail where a few links got bent and then removed without it being fixed afterwards. To see if the chain is worn, measure it with a special tool made for that, or just use a ruler. Look at youtube on how to do that. Given that it's too short, it should be replaced anyways. I'd replace that first before replacing the cassette.

  12. #12
    mtbr member
    Reputation:
    Join Date
    Mar 2018
    Posts
    14
    Thank you so much for your replies guys! What kind of a chain and cassette do I need for this bike?? Do they come in different models? Sizes? Numbers? What should I look for??

  13. #13
    mtbr member
    Reputation:
    Join Date
    Dec 2017
    Posts
    462
    Chains are designed for the number of gears of the rear cassette. As the number of gears go up, a narrower chain is needed. In your case, you'll need a chain designed for 6/7/8 speeds: Shimano CN-HG71 6/7/8 Speed Chain | Jenson USA. For the rear sprockets, you first need to confirm if it's a freehub style cassette or a freewheel style. 7 speed can be either. See here for instructions on how to check that: https://www.parktool.com/blog/repair...freewheel-type. If it is a freehub cassette, then this is the one you would need: Shimano HG50 7-SPEED Cassette | Jenson USA. If it's a freewheel, this one should work: DNP Epoch 7 Speed Freewheel | Jenson USA. You should count the number of teeth on the smallest sprocket and the largest to see what range it is. You may not be able to easily find an exact equivalent.

    Note that there are specialty tools needed for removing and installing the chain, and for removing and installing the cassette. If you want to get into maintaining your own bike(s), then these are must have tools.

    The other thing you should decide is if you want to spend more money on this bike. Looking at the specs of it, it is designed for easy trail use, paved paths, etc. You posted this in "All Mountain" which leads me to think that you are wanting something for more challenging trails. If that's the case, I would sell the bike as-is and look for something better.

  14. #14
    755872
    Guest
    Can't see your chain rings but you'll want to check them too. If they look like shark fins (not symmetrical) or the bottom of the tooth isn't flattened (should be pretty round). Wear doesn't hit one part of the drive train and skip another. By the time you fix everything, you may be into the bike for more than your paid.

  15. #15
    mtbr member
    Reputation: nauc's Avatar
    Join Date
    Sep 2009
    Posts
    3,024
    chain looks too short, watch this.. https://www.youtube.com/watch?v=O0YibMDWBAw

    cassette looks worn as hell

  16. #16
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    2,552
    I think your best bet is buying a microbrew 6 pack and posting in your regional forum. I bet there's some other guy on here in Charlotte who'd help you out!

    Sent from my Moto G (5) Plus using Tapatalk

  17. #17
    BOOM goes the dynamite!
    Reputation: noapathy's Avatar
    Join Date
    Jun 2008
    Posts
    3,821
    Chain length looks OK thanks to the second batch of pics. OP, look up cross-chaining and just don't do it.

    I agree the cassette/freehub looks worn out, so the chain is likely toast.

  18. #18
    mtbr member
    Reputation:
    Join Date
    Aug 2017
    Posts
    353
    Seems like a good time for a speech about shifting and "cross chaining" as mentioned above. You need to avoid using the small ring in front combined with the smallest ring in the rear, or especially the large ring in the front with the large ring in the back. This runs the chain at an angle and will wear it out faster. Large to large is especially a no no because it will put a strain on the chain, and derailleur due to pulling it tight to the largest sized rings. If the chain is installed too short, or has been broken and repaired, leaving it short, you can strain or even break your rear deraileur, chain. So if you are on the small ring in the front, and find yourself wanting the smallest couple rear cogs (like a downhill), you need to move to the middle ring in front and this will put you back in the middle of the rear cassette, and keep strain off the drivetrain. Same with the big ring in the front. If you start finding you need easier gears, and you are near the biggest couple cogs on the back, drop it to the middle ring. The middle ring is ok with going the full range in the rear usually, but I'd think about shifting habits and practice your shifting so as not to cross chain.

  19. #19
    mtbr member
    Reputation:
    Join Date
    Mar 2018
    Posts
    14
    I'm about to go back to the shop in an hour and give the shop a piece of my mind. I don't know if this old southern man has ever dealt with a kid from Brooklyn but he's about to find out. I flat out told him that my shifting was crap before i gave him my bike for a "delux tuneup" doesn;t look like he checked anything other than turning a few screws and a little knob in the back. He was supposed to take off my drivetrain, clean it and put it back in, the chain is still dirty AF it looks like he just ran a rag through the outer portion of it and the pulley is as dirty as it was before. I paid $35 extra because he charged me for a little steering wheel round piece that was apparently broken that he replaced. Charged me $25 for labor and $10 for the piece without calling me and asking if i want him to do this and now without looking at anything he proposed the issue is with the chain and the cassette that needs to be replaced and told me he'd do it for $60 without labor (like he's doing me a solid). My intuition is telling me I got f*cked.

  20. #20
    mtbr member
    Reputation:
    Join Date
    Mar 2018
    Posts
    14
    Hi guys so I went to the shop and argued with the guy for a bit, he put on a new chain and cassette to prove to me that it's what's causing the issue and that didn't solve the problem...he bickered a bit, checked the hanger with the tool to see if it was bent unwillingly and added two more links to the new chain but still couldn't figure out what is wrong. So, I got a new chain and a cassette for free so that's a win, and I now know the hanger isn't bent...what else could it be?? The derailleur itself??

  21. #21
    mtbr member
    Reputation: MSU Alum's Avatar
    Join Date
    Aug 2009
    Posts
    3,242
    The OP said the bad gears on the rear were the 3/4/5 on a 7 speed. It seems unlikely that cross chaining is an issue. If it were, the first and 7th would be more likely to cause problems.

  22. #22
    BOOM goes the dynamite!
    Reputation: noapathy's Avatar
    Join Date
    Jun 2008
    Posts
    3,821
    Quote Originally Posted by MSU Alum View Post
    The OP said the bad gears on the rear were the 3/4/5 on a 7 speed. It seems unlikely that cross chaining is an issue. If it were, the first and 7th would be more likely to cause problems.
    It'd also reduce the likelihood that it's a chain length issue (could still contribute to the overall poor performance). Bent derailleur? Cable catching somewhere? Shifter not indexing properly? Any of those should be an easy diagnosis for any halfway decent shop.
    Last edited by noapathy; 03-26-2018 at 12:56 PM.

  23. #23
    Short-Change-Hero
    Reputation: gregnash's Avatar
    Join Date
    Jul 2010
    Posts
    5,459
    Sounds like you need to go to a different shop as these guys are either not an honest shop or dont know what they are doing.

    While you say that the shop tested with the derailleur tool, I would take it else where to have it checked out because based on the other stuff I would not trust their judgement. If nothing else it looks like it is time for you to get a YouTube education on full bike maintenance.

  24. #24
    mtbr member
    Reputation:
    Join Date
    Aug 2017
    Posts
    353
    Quote Originally Posted by gregnash View Post
    If nothing else it looks like it is time for you to get a YouTube education on full bike maintenance.
    This is what I was thinking. It isn't rocket science to work on your bike if you are handy and have any experience with basic tools, OR a willingness to take it slow and methodical while you learn. If this is a cheaper starter bike, it is a great candidate to learn on because any mistakes will be less costly. With YouTube, you can find a wealth of information and how to's showing you exactly what to do. The cost of tools will usually roughly be a wash vs the cost of a shop doing it on the first use, but every time after that you're way ahead of the game on expense, hassle (bike breaks, fix it as soon as you can get the parts) and if you do it yourself, you can do it right without having to wonder if they did a careful correct job. If you ride a lot, you are going to break and wear out stuff, so it's a handy skill to have.

  25. #25
    Short-Change-Hero
    Reputation: gregnash's Avatar
    Join Date
    Jul 2010
    Posts
    5,459
    The other thing that I was thinking of as I was reading the responses is...
    1. Derailleur or hanger could be bent and the shop just not using properly
    2. front chainrings could be so out of whack and used that they are not able to adequately hold a chain.
    3. shifter cables could be so out of whack/stretched that shifting is complete garbage and not allowing to transition between gears properly
    4. (and possibly the worst) frame rear triangle could be bent to the point that it will not hold a proper line for the chain.

    Thing is in the first photos of the cassette you can definitely tell the cassette is worn to the point of needing to have it replaced (see some of the teeth look like shark fins). But it looks like that as well as a new chain have been added. If nothing else, go subscribe to the GMBN and ParkTools youtube channels as they have plenty of tutorials on how to work on stuff like. The hard part is that this is a 3x7 drivetrain which means it is OLD and so videos may be a bit clunky to learn from, but the basic premis for working on any drivetrain will come across. Take all the adjustments slowly allowing time for you to get a feel for what each does and how much each turn will make changes because there are multiple points that changes can be made.

  26. #26
    mtbr member
    Reputation: sml-2727's Avatar
    Join Date
    Nov 2013
    Posts
    1,625
    Do they have bike shops where you live?
    2018 Canyon Spectral
    2016 Ibis Ripley OG
    2016 Salsa Bucksaw

  27. #27
    mtbr member
    Reputation:
    Join Date
    Aug 2018
    Posts
    20
    I just got a new bike that I was told it was ready to go by the shop. The chain would derail 2-4 times in 5 miles and slip even more. They put on a new cassette, rear sprocket and chain and it has been perfect. I was told different ridding styles can bring out different problems.

Similar Threads

  1. Replies: 0
    Last Post: 07-17-2015, 09:49 AM
  2. Just Purchased My First Mountain Bike (Hardtail)
    By kanewtz in forum Beginner's Corner
    Replies: 14
    Last Post: 04-22-2015, 12:16 PM
  3. Just purchased my first mountain bike
    By tkeon286 in forum Beginner's Corner
    Replies: 1
    Last Post: 03-16-2015, 06:21 PM
  4. Replies: 0
    Last Post: 06-17-2014, 09:42 AM
  5. Noob here, just purchased first mountain bike
    By Stek23 in forum Beginner's Corner
    Replies: 6
    Last Post: 04-09-2012, 02:50 PM

Members who have read this thread: 48

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

mtbr.com and the ConsumerReview Network are business units of Invenda Corporation

(C) Copyright 1996-2018. All Rights Reserved.