Mongoose index 3.0

Yes, all bikes have handlebar height adjustment.

How to Adjust the Handle Bars on a Mongoose Mountain ...

DIY Mountain Bike https://www.diymountainbike.com > adjust-handle-bar...
This is done by loosening the bolt and clamp on the front of the stem. Insert a 6mm Allen wrench into the bolt head and turn until the handle bars roll freely.

How to Raise Handlebars on Mongoose Mountain Bike

mtbrules.com https://mtbrules.com > how-to-raise-handlebars-on-mo...
Oct 2, 2022 - You can adjust the handlebars from front to back by loosening the clamp bolt in the stem's front. Insert a 6 mm Allen wrench into the bolt head.

How to Raise the Handlebars on a Mongoose

SportsRec https://www.sportsrec.com > Fitness > Strength Training
Jun 29, 2011 - Other options for raising Mongoose handlebars are adding a new riser bar, which can give 1 to 5 inches of height for your handlebars. A steer- ...

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Product Manuals

Mongoose https://www.mongoose.com > pages > product-manuals
The Mongoose owner's manual contains important safety, performance and maintenance information. Read the manual before taking your first ride on your new ...

"Size of what? chainwheel, crank length, Bottom bracket spindle length? Not possible to say in any case, as manufacturer specs can change, even in a model year. Take to a bike co-op or bike shop for advice or search online for "replace crankset".

Loosen rear axle nuts.
Pull back on the rear wheel until the chain is tight, then move forward just a bit and tighten both sides with your hands at the same time. Try to keep the wheel centered.
Tighten the right axle nut, center the wheel and then tighten the rear.
Turn the crank slowly. The chain should have slight play at the tightest point in the crank rotation.
If the chain is too tight or too loose loosen the right nut and move the axle forward or back, tighten and retest.
When tension seems OK loosen left nut and center the wheel, then retest.

I’m happy to help further over the phone at https://www.6ya.com/expert/donald_f2ed37026a3ac881

Usually takes special tools. The pedals should be removed, the crankset is either a single arm or a 3 piece unit. If its a single, remove large nut on one side of the crank, usually the left side. Then remove the inside cone, the bearings are visible and should be removed. The last is the crankarm itself. It will only come out if thew left side bear is removed. Twist it gently and it usually comes out at the 3 o'clock position.
If its a 3 piece crankset, special tools are need to remove. SAuggest you take it to the nearest bike shop.

It sounds like you need a set of METRIC allen wrenches. Then the 4mm one will fit. Rgds, Scott

For the gear problem.Find the shifter.Use a pair of pliers and loosen the nut where the cable is passing through the shifter.Now withe the pliers pull the cable tight.Very tight.Spray the shifter with WD-40.That should fix it.


For the front rim,tighten all the spokes.Pliers will work,but a spoke too; will make the job faster.

i have never fixed this bike but normally there is an allen wrench bolt right on top of the shaft you have to loosen it (not take it out there is a tightening nut at the other end of the that you want to stay on) then after it is lose you should be able to adjust it but if not you will have to loosen or take of the first bolt down the shaft and that should make it able to be adjusted i hope this helps
SabiousOne

Find your type here...

http://www.parktool.com/blog/repair-help/categories/crank-service

It seems you will need more tension on the chain. Place the bike upside down, loosen the nuts, grab a broom stick or bar and place it between the rear tire and crank housing straight up and down with the handle bars away from you, push the bar away from you. When done properly the tire will come toward you tightening the slack in the chain. While you hold pressure on the bar tighten the nuts and WALLA.

im certain that model has a 3 piece crank set up. the inner crank bearing jam nut has loosened up or the bearings themselves have gone bad.first check to see if its tight, if it is then it will require a replacement set of bearing that are a pretty standard size to all bikes and can be purchased at nearly every bike shop.