Rotor bolt lengths

[AndreJvVZA]

Hi guys,

 

Just checking if I'm overly cautious. I got a boost hub for a new fork. The bike shop rebuilt the wheel and fitted the rotor and used a 5mm spacer to compensate for the allignment.

 

I am fitting new rotors now and discovered that the original bolts were used with the spacer. Does anyone know if this is ok? The bolts screw in only by a few threads and not with most of the thread as I am use to.

 

In my mind it's not safe...... Am I wrong or should I get longer bolts?

 

Thanks in advance for your feedback.

 

Andre

[dasilvarsa]

It would be better to get longer bolts (if you can get them).

[Capricorn]

Hi guys,

 

Just checking if I'm overly cautious. I got a boost hub for a new fork. The bike shop rebuilt the wheel and fitted the rotor and used a 5mm spacer to compensate for the allignment.

 

I am fitting new rotors now and discovered that the original bolts were used with the spacer. Does anyone know if this is ok? The bolts screw in only by a few threads and not with most of the thread as I am use to.

 

In my mind it's not safe...... Am I wrong or should I get longer bolts?

 

Thanks in advance for your feedback.

 

Andre

 

is that a boost fork as well?

[Jewbacca]

Huh?

 

If you got a boost hub to go with your boost fork, there should be no spacer.

 

There would only be a spacer if they used a Boost adapter on your original hub.

 

Either they lied or you got the wrong end of the stick.

 

In most cases the adapter kits and spacers come with longer bolts. Your bike shop ripped you off. You want that rotor as firmly in place as possible!

[AndreJvVZA]

is that a boost fork as well?

Jip its a boost fork and was told the boost hub was at a good price and better than getting adaptors for my old hub. Also thought that all would be in order and only discovered the spacer today.

[madmarc]

Jip its a boost fork and was told the boost hub was at a good price and better than getting adaptors for my old hub. Also thought that all would be in order and only discovered the spacer today.

 

Then its not a boost hub, if it were there would be no need for a spacer. You could have done the same with your old hub simply re-dished the wheel and used the boost spacer. The bolts def need to be longer by the width of the spacer 5mm in your case.

 

I had to use a boost spacer kit on my hope rear hub and it came with longer bolts.

[Sllab]

From a design perspective the rule of thumb for an M5 thread would be 5 to 10mm of engagement for secure fastening. So, if the spacer is 5mm wide and the original bolts have been used, it would seem that the original designer allowed for something of the order of 7mm engagement. Aggravating factor is the fact that you are screwing a steel thread into an aluminium body, which is weaker than steel on steel. Long story short - thats a dangerous setup. Get longer bolts asap - you can get them from most specialist shops in stainless steel that are more than adequate for the job. Would suggest 5mm more thread than you currently have.